diff --git a/lldb/include/lldb/Host/common/NativeProcessProtocol.h b/lldb/include/lldb/Host/common/NativeProcessProtocol.h
--- a/lldb/include/lldb/Host/common/NativeProcessProtocol.h
+++ b/lldb/include/lldb/Host/common/NativeProcessProtocol.h
@@ -85,6 +85,9 @@
   Status ReadMemoryWithoutTrap(lldb::addr_t addr, void *buf, size_t size,
                                size_t &bytes_read);
 
+  virtual Status ReadMemoryTags(int32_t type, lldb::addr_t addr, size_t len,
+                                std::vector<uint8_t> &tags);
+
   /// Reads a null terminated string from memory.
   ///
   /// Reads up to \p max_size bytes of memory until it finds a '\0'.
diff --git a/lldb/include/lldb/Host/linux/Ptrace.h b/lldb/include/lldb/Host/linux/Ptrace.h
--- a/lldb/include/lldb/Host/linux/Ptrace.h
+++ b/lldb/include/lldb/Host/linux/Ptrace.h
@@ -50,6 +50,12 @@
 #define ARCH_GET_FS 0x1003
 #define ARCH_GET_GS 0x1004
 #endif
+#ifndef PTRACE_PEEKMTETAGS
+#define PTRACE_PEEKMTETAGS 33
+#endif
+#ifndef PTRACE_POKEMTETAGS
+#define PTRACE_POKEMTETAGS 34
+#endif
 
 #define LLDB_PTRACE_NT_ARM_TLS 0x401 // ARM TLS register
 
diff --git a/lldb/include/lldb/Utility/StringExtractorGDBRemote.h b/lldb/include/lldb/Utility/StringExtractorGDBRemote.h
--- a/lldb/include/lldb/Utility/StringExtractorGDBRemote.h
+++ b/lldb/include/lldb/Utility/StringExtractorGDBRemote.h
@@ -169,6 +169,8 @@
     eServerPacketType_jTraceConfigRead, // deprecated
 
     eServerPacketType_jLLDBTraceSupportedType,
+
+    eServerPacketType_qMemTags,
   };
 
   ServerPacketType GetServerPacketType() const;
diff --git a/lldb/packages/Python/lldbsuite/test/decorators.py b/lldb/packages/Python/lldbsuite/test/decorators.py
--- a/lldb/packages/Python/lldbsuite/test/decorators.py
+++ b/lldb/packages/Python/lldbsuite/test/decorators.py
@@ -823,6 +823,40 @@
     """Skip this test if the environment is set up to run LLDB *itself* under ASAN."""
     return skipTestIfFn(is_running_under_asan)(func)
 
+def skipUnlessAArch64MTELinuxCompiler(func):
+    """Decorate the item to skip test unless MTE is supported by the test compiler."""
+
+    def is_toolchain_with_mte(self):
+        compiler_path = self.getCompiler()
+        compiler = os.path.basename(compiler_path)
+        f = tempfile.NamedTemporaryFile()
+        if lldbplatformutil.getPlatform() == 'windows':
+            return "MTE tests are not compatible with 'windows'"
+
+        cmd = "echo 'int main() {}' | %s -x c -o %s -" % (compiler_path, f.name)
+        if os.popen(cmd).close() is not None:
+            # Cannot compile at all, don't skip the test
+            # so that we report the broken compiler normally.
+            return None
+
+        # We need the Linux headers and ACLE MTE intrinsics
+        test_src = """
+            #include <asm/hwcap.h>
+            #include <arm_acle.h>
+            #ifndef HWCAP2_MTE
+            #error
+            #endif
+            int main() {
+                void* ptr = __arm_mte_create_random_tag((void*)(0), 0);
+            }"""
+        cmd = "echo '%s' | %s -march=armv8.5-a+memtag -x c -o %s -" % (test_src, compiler_path, f.name)
+        if os.popen(cmd).close() is not None:
+            return "Toolchain does not support MTE"
+        return None
+
+    return skipTestIfFn(is_toolchain_with_mte)(func)
+
+
 def _get_bool_config(key, fail_value = True):
     """
     Returns the current LLDB's build config value.
diff --git a/lldb/source/Host/common/NativeProcessProtocol.cpp b/lldb/source/Host/common/NativeProcessProtocol.cpp
--- a/lldb/source/Host/common/NativeProcessProtocol.cpp
+++ b/lldb/source/Host/common/NativeProcessProtocol.cpp
@@ -54,6 +54,12 @@
   return Status("not implemented");
 }
 
+lldb_private::Status
+NativeProcessProtocol::ReadMemoryTags(int32_t type, lldb::addr_t addr,
+                                      size_t len, std::vector<uint8_t> &tags) {
+  return Status("not implemented");
+}
+
 llvm::Optional<WaitStatus> NativeProcessProtocol::GetExitStatus() {
   if (m_state == lldb::eStateExited)
     return m_exit_status;
diff --git a/lldb/source/Plugins/Process/Linux/NativeProcessLinux.h b/lldb/source/Plugins/Process/Linux/NativeProcessLinux.h
--- a/lldb/source/Plugins/Process/Linux/NativeProcessLinux.h
+++ b/lldb/source/Plugins/Process/Linux/NativeProcessLinux.h
@@ -78,6 +78,9 @@
 
   llvm::Error DeallocateMemory(lldb::addr_t addr) override;
 
+  Status ReadMemoryTags(int32_t type, lldb::addr_t addr, size_t len,
+                        std::vector<uint8_t> &tags) override;
+
   size_t UpdateThreads() override;
 
   const ArchSpec &GetArchitecture() const override { return m_arch; }
diff --git a/lldb/source/Plugins/Process/Linux/NativeProcessLinux.cpp b/lldb/source/Plugins/Process/Linux/NativeProcessLinux.cpp
--- a/lldb/source/Plugins/Process/Linux/NativeProcessLinux.cpp
+++ b/lldb/source/Plugins/Process/Linux/NativeProcessLinux.cpp
@@ -1322,6 +1322,47 @@
   return llvm::Error::success();
 }
 
+Status NativeProcessLinux::ReadMemoryTags(int32_t type, lldb::addr_t addr,
+                                          size_t len,
+                                          std::vector<uint8_t> &tags) {
+  llvm::Expected<NativeRegisterContextLinux::MemoryTaggingDetails> details =
+      GetCurrentThread()->GetRegisterContext().GetMemoryTaggingDetails(type);
+  if (!details)
+    return Status(details.takeError());
+
+  // Ignore 0 length read
+  if (!len)
+    return Status();
+
+  // lldb will align the range it requests but it is not required to by
+  // the protocol so we'll do it again just in case.
+  // Also remove the tag here. ptrace may work with it present
+  // but that is not guaranteed.
+  MemoryTagManager::TagRange range(details->manager->RemoveLogicalTag(addr),
+                                   len);
+  range = details->manager->ExpandToGranule(range);
+
+  tags.resize((range.GetByteSize() / details->manager->GetGranuleSize()) *
+              details->manager->GetBytesPerTag());
+
+  struct iovec tags_vec;
+  tags_vec.iov_base = &tags[0];
+  tags_vec.iov_len = tags.size();
+
+  Status error = NativeProcessLinux::PtraceWrapper(
+      details->ptrace_read_req, GetID(),
+      reinterpret_cast<void *>(range.GetRangeBase()),
+      static_cast<void *>(&tags_vec), 0, nullptr);
+
+  if (error.Fail())
+    return error;
+
+  if (tags_vec.iov_len != tags.size())
+    return Status("Got unexpected number of memory tag bytes from ptrace.");
+
+  return error;
+}
+
 size_t NativeProcessLinux::UpdateThreads() {
   // The NativeProcessLinux monitoring threads are always up to date with
   // respect to thread state and they keep the thread list populated properly.
diff --git a/lldb/source/Plugins/Process/Linux/NativeRegisterContextLinux.h b/lldb/source/Plugins/Process/Linux/NativeRegisterContextLinux.h
--- a/lldb/source/Plugins/Process/Linux/NativeRegisterContextLinux.h
+++ b/lldb/source/Plugins/Process/Linux/NativeRegisterContextLinux.h
@@ -11,6 +11,8 @@
 
 #include "Plugins/Process/Utility/NativeRegisterContextRegisterInfo.h"
 #include "lldb/Host/common/NativeThreadProtocol.h"
+#include "lldb/Target/MemoryTagManager.h"
+#include "llvm/Support/Error.h"
 
 namespace lldb_private {
 namespace process_linux {
@@ -55,6 +57,18 @@
   /// they are supported.
   virtual llvm::Optional<MmapData> GetMmapData() { return llvm::None; }
 
+  struct MemoryTaggingDetails {
+    std::unique_ptr<MemoryTagManager> manager;
+    int ptrace_read_req;
+    int ptrace_write_req;
+  };
+  virtual llvm::Expected<MemoryTaggingDetails>
+  GetMemoryTaggingDetails(int32_t type) {
+    return llvm::createStringError(
+        llvm::inconvertibleErrorCode(),
+        "Architecture does not support memory tagging");
+  }
+
 protected:
   lldb::ByteOrder GetByteOrder() const;
 
diff --git a/lldb/source/Plugins/Process/Linux/NativeRegisterContextLinux_arm64.h b/lldb/source/Plugins/Process/Linux/NativeRegisterContextLinux_arm64.h
--- a/lldb/source/Plugins/Process/Linux/NativeRegisterContextLinux_arm64.h
+++ b/lldb/source/Plugins/Process/Linux/NativeRegisterContextLinux_arm64.h
@@ -85,6 +85,9 @@
   // Debug register type select
   enum DREGType { eDREGTypeWATCH = 0, eDREGTypeBREAK };
 
+  llvm::Expected<MemoryTaggingDetails>
+  GetMemoryTaggingDetails(int32_t type) override;
+
 protected:
 
   Status ReadGPR() override;
diff --git a/lldb/source/Plugins/Process/Linux/NativeRegisterContextLinux_arm64.cpp b/lldb/source/Plugins/Process/Linux/NativeRegisterContextLinux_arm64.cpp
--- a/lldb/source/Plugins/Process/Linux/NativeRegisterContextLinux_arm64.cpp
+++ b/lldb/source/Plugins/Process/Linux/NativeRegisterContextLinux_arm64.cpp
@@ -21,6 +21,7 @@
 #include "Plugins/Process/Linux/NativeProcessLinux.h"
 #include "Plugins/Process/Linux/Procfs.h"
 #include "Plugins/Process/POSIX/ProcessPOSIXLog.h"
+#include "Plugins/Process/Utility/MemoryTagManagerAArch64MTE.h"
 #include "Plugins/Process/Utility/RegisterInfoPOSIX_arm64.h"
 
 // System includes - They have to be included after framework includes because
@@ -1152,4 +1153,16 @@
   return expedited_reg_nums;
 }
 
+llvm::Expected<NativeRegisterContextLinux::MemoryTaggingDetails>
+NativeRegisterContextLinux_arm64::GetMemoryTaggingDetails(int32_t type) {
+  if (type == MemoryTagManagerAArch64MTE::eMTE_allocation) {
+    return MemoryTaggingDetails{
+        std::make_unique<MemoryTagManagerAArch64MTE>(),
+        PTRACE_PEEKMTETAGS, PTRACE_POKEMTETAGS};
+  }
+
+  return llvm::createStringError(llvm::inconvertibleErrorCode(),
+                                 "Unknown AArch64 memory tag type %d", type);
+}
+
 #endif // defined (__arm64__) || defined (__aarch64__)
diff --git a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerLLGS.h b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerLLGS.h
--- a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerLLGS.h
+++ b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerLLGS.h
@@ -201,6 +201,8 @@
 
   PacketResult Handle_g(StringExtractorGDBRemote &packet);
 
+  PacketResult Handle_qMemTags(StringExtractorGDBRemote &packet);
+
   void SetCurrentThreadID(lldb::tid_t tid);
 
   lldb::tid_t GetCurrentThreadID() const;
diff --git a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerLLGS.cpp b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerLLGS.cpp
--- a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerLLGS.cpp
+++ b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerLLGS.cpp
@@ -13,6 +13,7 @@
 
 #include <chrono>
 #include <cstring>
+#include <limits>
 #include <thread>
 
 #include "GDBRemoteCommunicationServerLLGS.h"
@@ -207,6 +208,10 @@
   RegisterMemberFunctionHandler(StringExtractorGDBRemote::eServerPacketType_g,
                                 &GDBRemoteCommunicationServerLLGS::Handle_g);
 
+  RegisterMemberFunctionHandler(
+      StringExtractorGDBRemote::eServerPacketType_qMemTags,
+      &GDBRemoteCommunicationServerLLGS::Handle_qMemTags);
+
   RegisterPacketHandler(StringExtractorGDBRemote::eServerPacketType_k,
                         [this](StringExtractorGDBRemote packet, Status &error,
                                bool &interrupt, bool &quit) {
@@ -3511,6 +3516,70 @@
   return SendOKResponse();
 }
 
+GDBRemoteCommunication::PacketResult
+GDBRemoteCommunicationServerLLGS::Handle_qMemTags(
+    StringExtractorGDBRemote &packet) {
+  Log *log(GetLogIfAnyCategoriesSet(LIBLLDB_LOG_PROCESS));
+
+  // Ensure we have a process.
+  if (!m_debugged_process_up ||
+      (m_debugged_process_up->GetID() == LLDB_INVALID_PROCESS_ID)) {
+    LLDB_LOGF(
+        log,
+        "GDBRemoteCommunicationServerLLGS::%s failed, no process available",
+        __FUNCTION__);
+    return SendErrorResponse(1);
+  }
+
+  // We are expecting
+  // qMemTags:<hex address>,<hex length>:<hex type>
+
+  // Address
+  packet.SetFilePos(strlen("qMemTags:"));
+  const char *current_char = packet.Peek();
+  if (!current_char || *current_char == ',')
+    return SendIllFormedResponse(packet, "Missing address in qMemTags packet");
+  const lldb::addr_t addr = packet.GetHexMaxU64(/*little_endian=*/false, 0);
+
+  // Length
+  char previous_char = packet.GetChar();
+  current_char = packet.Peek();
+  // If we don't have a separator or the length field is empty
+  if (previous_char != ',' || (current_char && *current_char == ':'))
+    return SendIllFormedResponse(packet,
+                                 "Invalid addr,length pair in qMemTags packet");
+
+  if (packet.GetBytesLeft() < 1)
+    return SendIllFormedResponse(
+        packet, "Too short qMemtags: packet (looking for length)");
+  const size_t length = packet.GetHexMaxU64(/*little_endian=*/false, 0);
+
+  // Type
+  const char *invalid_type_err = "Invalid type field in qMemTags: packet";
+  if (packet.GetBytesLeft() < 1 || packet.GetChar() != ':')
+    return SendIllFormedResponse(packet, invalid_type_err);
+
+  int32_t type =
+      packet.GetS32(std::numeric_limits<int32_t>::max(), /*base=*/16);
+  if (type == std::numeric_limits<int32_t>::max() ||
+      // To catch inputs like "123aardvark" that will parse but clearly aren't
+      // valid in this case.
+      packet.GetBytesLeft()) {
+    return SendIllFormedResponse(packet, invalid_type_err);
+  }
+
+  StreamGDBRemote response;
+  std::vector<uint8_t> tags;
+  Status error =
+      m_debugged_process_up->ReadMemoryTags(type, addr, length, tags);
+  if (error.Fail())
+    return SendErrorResponse(1);
+
+  response.PutChar('m');
+  response.PutBytesAsRawHex8(tags.data(), tags.size());
+  return SendPacketNoLock(response.GetString());
+}
+
 void GDBRemoteCommunicationServerLLGS::MaybeCloseInferiorTerminalConnection() {
   Log *log(GetLogIfAnyCategoriesSet(LIBLLDB_LOG_PROCESS));
 
diff --git a/lldb/source/Utility/StringExtractorGDBRemote.cpp b/lldb/source/Utility/StringExtractorGDBRemote.cpp
--- a/lldb/source/Utility/StringExtractorGDBRemote.cpp
+++ b/lldb/source/Utility/StringExtractorGDBRemote.cpp
@@ -220,6 +220,8 @@
         return eServerPacketType_qMemoryRegionInfoSupported;
       if (PACKET_STARTS_WITH("qModuleInfo:"))
         return eServerPacketType_qModuleInfo;
+      if (PACKET_STARTS_WITH("qMemTags:"))
+        return eServerPacketType_qMemTags;
       break;
 
     case 'P':
diff --git a/lldb/test/API/tools/lldb-server/memory-tagging/Makefile b/lldb/test/API/tools/lldb-server/memory-tagging/Makefile
new file mode 100644
--- /dev/null
+++ b/lldb/test/API/tools/lldb-server/memory-tagging/Makefile
@@ -0,0 +1,4 @@
+C_SOURCES := main.c
+CFLAGS_EXTRAS := -march=armv8.5-a+memtag
+
+include Makefile.rules
diff --git a/lldb/test/API/tools/lldb-server/memory-tagging/TestGdbRemoteMemoryTagging.py b/lldb/test/API/tools/lldb-server/memory-tagging/TestGdbRemoteMemoryTagging.py
new file mode 100644
--- /dev/null
+++ b/lldb/test/API/tools/lldb-server/memory-tagging/TestGdbRemoteMemoryTagging.py
@@ -0,0 +1,102 @@
+import gdbremote_testcase
+from lldbsuite.test.decorators import *
+from lldbsuite.test.lldbtest import *
+from lldbsuite.test import lldbutil
+
+class TestGdbRemoteMemoryTagging(gdbremote_testcase.GdbRemoteTestCaseBase):
+
+    mydir = TestBase.compute_mydir(__file__)
+
+    def check_qmemtags_response(self, body, expected):
+        self.test_sequence.add_log_lines(["read packet: $qMemTags:{}#00".format(body),
+                                          "send packet: ${}#00".format(expected),
+                                          ],
+                                         True)
+        self.expect_gdbremote_sequence()
+
+    @skipUnlessArch("aarch64")
+    @skipUnlessPlatform(["linux"])
+    @skipUnlessAArch64MTELinuxCompiler
+    def test_qmemtags_packets(self):
+        """ Test that qMemTags packets are parsed correctly and/or rejected. """
+
+        self.build()
+        self.set_inferior_startup_launch()
+        procs = self.prep_debug_monitor_and_inferior()
+
+        # Run the process
+        self.test_sequence.add_log_lines(
+            [
+                # Start running after initial stop
+                "read packet: $c#63",
+		# Match the address of the MTE page
+                {"type": "output_match", "regex": self.maybe_strict_output_regex(r"buffer: (.+)\r\n"),
+                 "capture": {1: "buffer"}},
+                # Now stop the inferior
+                "read packet: {}".format(chr(3)),
+                # And wait for the stop notification
+                {"direction": "send", "regex": r"^\$T[0-9a-fA-F]{2}thread:[0-9a-fA-F]+;"}],
+            True)
+
+        # Run the packet stream
+        context = self.expect_gdbremote_sequence()
+        self.assertIsNotNone(context)
+
+        # Grab the address
+        buf_address = context.get("buffer")
+        self.assertIsNotNone(buf_address)
+
+        # nil means we couldn't set up a tagged page because the
+        # target doesn't support it.
+        if buf_address == "(nil)":
+            self.skipTest("Target must support MTE.")
+
+        buf_address = int(buf_address, 16)
+
+        # In the tests below E03 means the packet wasn't formed correctly
+        # and E01 means it was but we had some other error acting upon it.
+
+        # Sanity check that address is correct
+        self.check_qmemtags_response("{:x},20:1".format(buf_address), "m0001")
+
+        # Invalid packets
+
+        # No content
+        self.check_qmemtags_response("", "E03")
+        # Only address
+        self.check_qmemtags_response("{:x}".format(buf_address), "E03")
+        # Only address and length
+        self.check_qmemtags_response("{:x},20".format(buf_address), "E03")
+        # Empty address
+        self.check_qmemtags_response(",20:1", "E03")
+        # Invalid addresses
+        self.check_qmemtags_response("aardvark,20:1", "E03")
+        self.check_qmemtags_response("-100,20:1", "E03")
+        self.check_qmemtags_response("cafe?,20:1", "E03")
+        # Empty length
+        self.check_qmemtags_response("{:x},:1".format(buf_address), "E03")
+        # Invalid lengths
+        self.check_qmemtags_response("{:x},food:1".format(buf_address), "E03")
+        self.check_qmemtags_response("{:x},-1:1".format(buf_address), "E03")
+        self.check_qmemtags_response("{:x},12??:1".format(buf_address), "E03")
+        # Empty type
+        self.check_qmemtags_response("{:x},10:".format(buf_address), "E03")
+        # Types we don't support
+        self.check_qmemtags_response("{:x},10:FF".format(buf_address), "E01")
+        # (even if the length of the read is zero)
+        self.check_qmemtags_response("{:x},0:FF".format(buf_address), "E01")
+        self.check_qmemtags_response("{:x},10:-1".format(buf_address), "E01")
+        self.check_qmemtags_response("{:x},10:+20".format(buf_address), "E01")
+        # Invalid type format
+        self.check_qmemtags_response("{:x},10:cat".format(buf_address), "E03")
+        self.check_qmemtags_response("{:x},10:?11".format(buf_address), "E03")
+
+        # Valid packets
+
+        # Reading nothing is allowed
+        self.check_qmemtags_response("{:x},0:1".format(buf_address), "m")
+        # A range that's already aligned
+        self.check_qmemtags_response("{:x},20:1".format(buf_address), "m0001")
+        # lldb-server should re-align the range
+        # Here we read from 1/2 way through a granule, into the next. Expands to 2 granules
+        self.check_qmemtags_response("{:x},10:1".format(buf_address+64-8), "m0304")
diff --git a/lldb/test/API/tools/lldb-server/memory-tagging/main.c b/lldb/test/API/tools/lldb-server/memory-tagging/main.c
new file mode 100644
--- /dev/null
+++ b/lldb/test/API/tools/lldb-server/memory-tagging/main.c
@@ -0,0 +1,48 @@
+#include <arm_acle.h>
+#include <asm/hwcap.h>
+#include <linux/mman.h>
+#include <stdio.h>
+#include <sys/auxv.h>
+#include <sys/mman.h>
+#include <sys/prctl.h>
+#include <unistd.h>
+
+void print_result(char *ptr) {
+  printf("buffer: %p\n", ptr);
+  // Wait for lldb-server to stop us
+  while (1) {
+  }
+}
+
+int main(int argc, char const *argv[]) {
+  if (prctl(PR_SET_TAGGED_ADDR_CTRL,
+            PR_TAGGED_ADDR_ENABLE | PR_MTE_TCF_SYNC |
+                // Allow all tags to be generated by the addg
+                // instruction __arm_mte_increment_tag produces.
+                (0xffff << PR_MTE_TAG_SHIFT),
+            0, 0, 0)) {
+    print_result(NULL);
+  }
+
+  size_t page_size = sysconf(_SC_PAGESIZE);
+  char *buf = mmap(0, sysconf(_SC_PAGESIZE), PROT_READ | PROT_WRITE | PROT_MTE,
+                   MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
+  if (buf == MAP_FAILED)
+    print_result(NULL);
+
+  // Set incrementing tags until end of the page
+  char *tagged_ptr = buf;
+  // This intrinsic treats the addresses as if they were untagged
+  while (__arm_mte_ptrdiff(tagged_ptr, buf) < page_size) {
+    // This sets the allocation tag
+    __arm_mte_set_tag(tagged_ptr);
+    // Set the tag of the next granule (hence +16) to the next
+    // tag value. Returns a new pointer with the new logical tag.
+    // Tag values wrap at 0xF so it'll cycle.
+    tagged_ptr = __arm_mte_increment_tag(tagged_ptr + 16, 1);
+  }
+
+  print_result(buf);
+
+  return 0;
+}