diff --git a/lld/MachO/Arch/ARM64.cpp b/lld/MachO/Arch/ARM64.cpp
--- a/lld/MachO/Arch/ARM64.cpp
+++ b/lld/MachO/Arch/ARM64.cpp
@@ -28,8 +28,8 @@
 struct ARM64 : TargetInfo {
   ARM64();
 
-  uint64_t getEmbeddedAddend(MemoryBufferRef, const section_64 &,
-                             const relocation_info) const override;
+  int64_t getEmbeddedAddend(MemoryBufferRef, const section_64 &,
+                            const relocation_info) const override;
   void relocateOne(uint8_t *loc, const Reloc &, uint64_t va,
                    uint64_t pc) const override;
 
@@ -77,8 +77,8 @@
   return relocAttrsArray[type];
 }
 
-uint64_t ARM64::getEmbeddedAddend(MemoryBufferRef mb, const section_64 &sec,
-                                  const relocation_info rel) const {
+int64_t ARM64::getEmbeddedAddend(MemoryBufferRef mb, const section_64 &sec,
+                                 const relocation_info rel) const {
   if (rel.r_type != ARM64_RELOC_UNSIGNED &&
       rel.r_type != ARM64_RELOC_SUBTRACTOR) {
     // All other reloc types should use the ADDEND relocation to store their
@@ -91,7 +91,7 @@
   const uint8_t *loc = buf + sec.offset + rel.r_address;
   switch (rel.r_length) {
   case 2:
-    return read32le(loc);
+    return static_cast<int32_t>(read32le(loc));
   case 3:
     return read64le(loc);
   default:
@@ -158,21 +158,28 @@
   value += r.addend;
   switch (r.type) {
   case ARM64_RELOC_BRANCH26:
+    checkInt(r, value - pc, 28);
     value = encodeBranch26(base, value - pc);
     break;
   case ARM64_RELOC_SUBTRACTOR:
   case ARM64_RELOC_UNSIGNED:
+    if (r.length == 2)
+      checkInt(r, value, 32);
     break;
   case ARM64_RELOC_POINTER_TO_GOT:
     if (r.pcrel)
       value -= pc;
+    checkInt(r, value, 32);
     break;
   case ARM64_RELOC_PAGE21:
   case ARM64_RELOC_GOT_LOAD_PAGE21:
-  case ARM64_RELOC_TLVP_LOAD_PAGE21:
+  case ARM64_RELOC_TLVP_LOAD_PAGE21: {
     assert(r.pcrel);
-    value = encodePage21(base, pageBits(value) - pageBits(pc));
+    int64_t pageDiff = pageBits(value) - pageBits(pc);
+    checkInt(r, pageDiff, 35);
+    value = encodePage21(base, pageDiff);
     break;
+  }
   case ARM64_RELOC_PAGEOFF12:
   case ARM64_RELOC_GOT_LOAD_PAGEOFF12:
   case ARM64_RELOC_TLVP_LOAD_PAGEOFF12:
diff --git a/lld/MachO/Arch/X86_64.cpp b/lld/MachO/Arch/X86_64.cpp
--- a/lld/MachO/Arch/X86_64.cpp
+++ b/lld/MachO/Arch/X86_64.cpp
@@ -25,8 +25,8 @@
 struct X86_64 : TargetInfo {
   X86_64();
 
-  uint64_t getEmbeddedAddend(MemoryBufferRef, const section_64 &,
-                             const relocation_info) const override;
+  int64_t getEmbeddedAddend(MemoryBufferRef, const section_64 &,
+                            const relocation_info) const override;
   void relocateOne(uint8_t *loc, const Reloc &, uint64_t va,
                    uint64_t relocVA) const override;
 
@@ -77,14 +77,14 @@
   }
 }
 
-uint64_t X86_64::getEmbeddedAddend(MemoryBufferRef mb, const section_64 &sec,
-                                   relocation_info rel) const {
+int64_t X86_64::getEmbeddedAddend(MemoryBufferRef mb, const section_64 &sec,
+                                  relocation_info rel) const {
   auto *buf = reinterpret_cast<const uint8_t *>(mb.getBufferStart());
   const uint8_t *loc = buf + sec.offset + rel.r_address;
 
   switch (rel.r_length) {
   case 2:
-    return read32le(loc) + pcrelOffset(rel.r_type);
+    return static_cast<int32_t>(read32le(loc)) + pcrelOffset(rel.r_type);
   case 3:
     return read64le(loc) + pcrelOffset(rel.r_type);
   default:
@@ -102,6 +102,10 @@
 
   switch (r.length) {
   case 2:
+    if (r.type == X86_64_RELOC_UNSIGNED)
+      checkUInt(r, value, 32);
+    else
+      checkInt(r, value, 32);
     write32le(loc, value);
     break;
   case 3:
diff --git a/lld/MachO/InputFiles.cpp b/lld/MachO/InputFiles.cpp
--- a/lld/MachO/InputFiles.cpp
+++ b/lld/MachO/InputFiles.cpp
@@ -264,7 +264,7 @@
     // and insert them. Storing addends in the instruction stream is
     // possible, but inconvenient and more costly at link time.
 
-    uint64_t pairedAddend = 0;
+    int64_t pairedAddend = 0;
     relocation_info relInfo = relInfos[i];
     if (target->hasAttr(relInfo.r_type, RelocAttrBits::ADDEND)) {
       pairedAddend = SignExtend64<24>(relInfo.r_symbolnum);
@@ -276,9 +276,9 @@
     if (relInfo.r_address & R_SCATTERED)
       fatal("TODO: Scattered relocations not supported");
 
-    uint64_t embeddedAddend = target->getEmbeddedAddend(mb, sec, relInfo);
+    int64_t embeddedAddend = target->getEmbeddedAddend(mb, sec, relInfo);
     assert(!(embeddedAddend && pairedAddend));
-    uint64_t totalAddend = pairedAddend + embeddedAddend;
+    int64_t totalAddend = pairedAddend + embeddedAddend;
     Reloc r;
     r.type = relInfo.r_type;
     r.pcrel = relInfo.r_pcrel;
diff --git a/lld/MachO/Relocations.h b/lld/MachO/Relocations.h
--- a/lld/MachO/Relocations.h
+++ b/lld/MachO/Relocations.h
@@ -59,13 +59,31 @@
   uint32_t offset = 0;
   // Adding this offset to the address of the referent symbol or subsection
   // gives the destination that this relocation refers to.
-  uint64_t addend = 0;
+  int64_t addend = 0;
   llvm::PointerUnion<Symbol *, InputSection *> referent = nullptr;
 };
 
 bool validateSymbolRelocation(const Symbol *, const InputSection *,
                               const Reloc &);
 
+/*
+ * v: The value the relocation is attempting to encode
+ * bits: The number of bits actually available to encode this relocation
+ */
+void reportRangeError(const Reloc &, const llvm::Twine &v, uint8_t bits,
+                      int64_t min, uint64_t max);
+
+inline void checkInt(const Reloc &r, int64_t v, int bits) {
+  if (v != llvm::SignExtend64(v, bits))
+    reportRangeError(r, llvm::Twine(v), bits, llvm::minIntN(bits),
+                     llvm::maxIntN(bits));
+}
+
+inline void checkUInt(const Reloc &r, uint64_t v, int bits) {
+  if ((v >> bits) != 0)
+    reportRangeError(r, llvm::Twine(v), bits, 0, llvm::maxUIntN(bits));
+}
+
 extern const RelocAttrs invalidRelocAttrs;
 
 } // namespace macho
diff --git a/lld/MachO/Relocations.cpp b/lld/MachO/Relocations.cpp
--- a/lld/MachO/Relocations.cpp
+++ b/lld/MachO/Relocations.cpp
@@ -39,4 +39,15 @@
   return valid;
 }
 
+void macho::reportRangeError(const Reloc &r, const Twine &v, uint8_t bits,
+                             int64_t min, uint64_t max) {
+  std::string hint;
+  if (auto *sym = r.referent.dyn_cast<Symbol *>())
+    hint = "; references " + toString(*sym);
+  // TODO: get location of reloc using something like LLD-ELF's getErrorPlace()
+  error("relocation " + target->getRelocAttrs(r.type).name +
+        " is out of range: " + v + " is not in [" + Twine(min) + ", " +
+        Twine(max) + "]" + hint);
+}
+
 const RelocAttrs macho::invalidRelocAttrs{"INVALID", RelocAttrBits::_0};
diff --git a/lld/MachO/Target.h b/lld/MachO/Target.h
--- a/lld/MachO/Target.h
+++ b/lld/MachO/Target.h
@@ -39,7 +39,7 @@
   virtual ~TargetInfo() = default;
 
   // Validate the relocation structure and get its addend.
-  virtual uint64_t
+  virtual int64_t
   getEmbeddedAddend(llvm::MemoryBufferRef, const llvm::MachO::section_64 &,
                     const llvm::MachO::relocation_info) const = 0;
   virtual void relocateOne(uint8_t *loc, const Reloc &, uint64_t va,
diff --git a/lld/test/MachO/invalid/range-check.s b/lld/test/MachO/invalid/range-check.s
new file mode 100644
--- /dev/null
+++ b/lld/test/MachO/invalid/range-check.s
@@ -0,0 +1,19 @@
+# REQUIRES: x86
+
+# RUN: llvm-mc -filetype=obj -triple=x86_64-apple-darwin %s -o %t.o
+# RUN: not %lld -lSystem -o %t %t.o 2>&1 | FileCheck %s
+# CHECK: error: relocation UNSIGNED is out of range: 8589938688 is not in [0, 4294967295]; references _foo
+# CHECK: error: relocation GOT_LOAD is out of range: 4294970473 is not in [-2147483648, 2147483647]; references _foo
+
+.globl _main, _foo
+
+_main:
+  movq _foo@GOTPCREL(%rip), %rax
+  ret
+
+.int _foo
+.zerofill __TEXT,bss,_zero,0xffffffff
+
+.data
+_foo:
+  .space 0