diff --git a/mlir/lib/Bytecode/Reader/BytecodeReader.cpp b/mlir/lib/Bytecode/Reader/BytecodeReader.cpp
--- a/mlir/lib/Bytecode/Reader/BytecodeReader.cpp
+++ b/mlir/lib/Bytecode/Reader/BytecodeReader.cpp
@@ -6,8 +6,6 @@
 //
 //===----------------------------------------------------------------------===//
 
-// TODO: Support for big-endian architectures.
-
 #include "mlir/Bytecode/BytecodeReader.h"
 #include "mlir/AsmParser/AsmParser.h"
 #include "mlir/Bytecode/BytecodeImplementation.h"
@@ -27,6 +25,7 @@
 #include "llvm/ADT/SmallString.h"
 #include "llvm/ADT/StringExtras.h"
 #include "llvm/ADT/StringRef.h"
+#include "llvm/Support/Endian.h"
 #include "llvm/Support/MemoryBufferRef.h"
 #include "llvm/Support/SaveAndRestore.h"
 #include "llvm/Support/SourceMgr.h"
@@ -203,8 +202,14 @@
     // Handle the overwhelming uncommon case where the value required all 8
     // bytes (i.e. a really really big number). In this case, the marker byte is
     // all zeros: `00000000`.
-    if (LLVM_UNLIKELY(result == 0))
-      return parseBytes(sizeof(result), reinterpret_cast<uint8_t *>(&result));
+    if (LLVM_UNLIKELY(result == 0)) {
+      llvm::support::ulittle64_t resultLE;
+      if (failed(parseBytes(sizeof(resultLE),
+                            reinterpret_cast<uint8_t *>(&resultLE))))
+        return failure();
+      result = resultLE;
+      return success();
+    }
     return parseMultiByteVarInt(result);
   }
 
@@ -305,12 +310,13 @@
            "unexpected number of trailing zeros in varint encoding");
 
     // Parse in the remaining bytes of the value.
-    if (failed(parseBytes(numBytes, reinterpret_cast<uint8_t *>(&result) + 1)))
+    llvm::support::ulittle64_t resultLE(result);
+    if (failed(parseBytes(numBytes, reinterpret_cast<uint8_t *>(&resultLE) + 1)))
       return failure();
 
     // Shift out the low-order bits that were used to mark how the value was
     // encoded.
-    result >>= (numBytes + 1);
+    result = resultLE >> (numBytes + 1);
     return success();
   }
 
diff --git a/mlir/lib/Bytecode/Writer/BytecodeWriter.cpp b/mlir/lib/Bytecode/Writer/BytecodeWriter.cpp
--- a/mlir/lib/Bytecode/Writer/BytecodeWriter.cpp
+++ b/mlir/lib/Bytecode/Writer/BytecodeWriter.cpp
@@ -21,6 +21,7 @@
 #include "llvm/ADT/SmallString.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/Support/raw_ostream.h"
+#include "llvm/Support/Endian.h"
 #include <cstddef>
 #include <cstdint>
 #include <cstring>
@@ -538,7 +539,8 @@
     if (LLVM_LIKELY(it >>= 7) == 0) {
       uint64_t encodedValue = (value << 1) | 0x1;
       encodedValue <<= (numBytes - 1);
-      emitBytes({reinterpret_cast<uint8_t *>(&encodedValue), numBytes});
+      llvm::support::ulittle64_t encodedValueLE(encodedValue);
+      emitBytes({reinterpret_cast<uint8_t *>(&encodedValueLE), numBytes});
       return;
     }
   }
@@ -546,7 +548,8 @@
   // If the value is too large to encode in a single byte, emit a special all
   // zero marker byte and splat the value directly.
   emitByte(0);
-  emitBytes({reinterpret_cast<uint8_t *>(&value), sizeof(value)});
+  llvm::support::ulittle64_t valueLE(value);
+  emitBytes({reinterpret_cast<uint8_t *>(&valueLE), sizeof(valueLE)});
 }
 
 //===----------------------------------------------------------------------===//
diff --git a/mlir/test/Bytecode/general.mlir b/mlir/test/Bytecode/general.mlir
--- a/mlir/test/Bytecode/general.mlir
+++ b/mlir/test/Bytecode/general.mlir
@@ -1,8 +1,5 @@
 // RUN: mlir-opt -allow-unregistered-dialect -emit-bytecode %s | mlir-opt -allow-unregistered-dialect | FileCheck %s
 
-// Bytecode currently does not support big-endian platforms
-// UNSUPPORTED: target=s390x-{{.*}}
-
 // CHECK-LABEL: "bytecode.test1"
 // CHECK-NEXT:    "unregistered.op"() {test_attr = #test.dynamic_singleton} : () -> ()
 // CHECK-NEXT:    "bytecode.empty"() : () -> ()
diff --git a/mlir/test/Bytecode/invalid/invalid-dialect_section.mlir b/mlir/test/Bytecode/invalid/invalid-dialect_section.mlir
--- a/mlir/test/Bytecode/invalid/invalid-dialect_section.mlir
+++ b/mlir/test/Bytecode/invalid/invalid-dialect_section.mlir
@@ -1,9 +1,6 @@
 // This file contains various failure test cases related to the structure of
 // the dialect section.
 
-// Bytecode currently does not support big-endian platforms
-// UNSUPPORTED: target=s390x-{{.*}}
-
 //===--------------------------------------------------------------------===//
 // Dialect Name
 //===--------------------------------------------------------------------===//
diff --git a/mlir/test/Bytecode/invalid/invalid-ir_section.mlir b/mlir/test/Bytecode/invalid/invalid-ir_section.mlir
--- a/mlir/test/Bytecode/invalid/invalid-ir_section.mlir
+++ b/mlir/test/Bytecode/invalid/invalid-ir_section.mlir
@@ -1,9 +1,6 @@
 // This file contains various failure test cases related to the structure of
 // the IR section.
 
-// Bytecode currently does not support big-endian platforms
-// UNSUPPORTED: target=s390x-{{.*}}
-
 //===--------------------------------------------------------------------===//
 // Operations
 //===--------------------------------------------------------------------===//
diff --git a/mlir/test/Bytecode/invalid/invalid-string_section.mlir b/mlir/test/Bytecode/invalid/invalid-string_section.mlir
--- a/mlir/test/Bytecode/invalid/invalid-string_section.mlir
+++ b/mlir/test/Bytecode/invalid/invalid-string_section.mlir
@@ -1,9 +1,6 @@
 // This file contains various failure test cases related to the structure of
 // the string section.
 
-// Bytecode currently does not support big-endian platforms
-// UNSUPPORTED: target=s390x-{{.*}}
-
 //===--------------------------------------------------------------------===//
 // Count
 //===--------------------------------------------------------------------===//
diff --git a/mlir/test/Bytecode/invalid/invalid-structure.mlir b/mlir/test/Bytecode/invalid/invalid-structure.mlir
--- a/mlir/test/Bytecode/invalid/invalid-structure.mlir
+++ b/mlir/test/Bytecode/invalid/invalid-structure.mlir
@@ -1,9 +1,6 @@
 // This file contains various failure test cases related to the structure of
 // a bytecode file.
 
-// Bytecode currently does not support big-endian platforms
-// UNSUPPORTED: target=s390x-{{.*}}
-
 //===--------------------------------------------------------------------===//
 // Version
 //===--------------------------------------------------------------------===//
diff --git a/mlir/test/Bytecode/invalid/invalid_attr_type_offset_section.mlir b/mlir/test/Bytecode/invalid/invalid_attr_type_offset_section.mlir
--- a/mlir/test/Bytecode/invalid/invalid_attr_type_offset_section.mlir
+++ b/mlir/test/Bytecode/invalid/invalid_attr_type_offset_section.mlir
@@ -1,9 +1,6 @@
 // This file contains various failure test cases related to the structure of
 // the attribute/type offset section.
 
-// Bytecode currently does not support big-endian platforms
-// UNSUPPORTED: target=s390x-{{.*}}
-
 //===--------------------------------------------------------------------===//
 // Offset
 //===--------------------------------------------------------------------===//
diff --git a/mlir/test/Bytecode/invalid/invalid_attr_type_section.mlir b/mlir/test/Bytecode/invalid/invalid_attr_type_section.mlir
--- a/mlir/test/Bytecode/invalid/invalid_attr_type_section.mlir
+++ b/mlir/test/Bytecode/invalid/invalid_attr_type_section.mlir
@@ -1,9 +1,6 @@
 // This file contains various failure test cases related to the structure of
 // the attribute/type offset section.
 
-// Bytecode currently does not support big-endian platforms
-// UNSUPPORTED: target=s390x-{{.*}}
-
 //===--------------------------------------------------------------------===//
 // Index
 //===--------------------------------------------------------------------===//
diff --git a/mlir/test/Bytecode/resources.mlir b/mlir/test/Bytecode/resources.mlir
--- a/mlir/test/Bytecode/resources.mlir
+++ b/mlir/test/Bytecode/resources.mlir
@@ -1,8 +1,5 @@
 // RUN: mlir-opt -emit-bytecode %s | mlir-opt | FileCheck %s
 
-// Bytecode currently does not support big-endian platforms
-// UNSUPPORTED: target=s390x-{{.*}}
-
 // CHECK-LABEL: @TestDialectResources
 module @TestDialectResources attributes {
   // CHECK: bytecode.test = dense_resource<decl_resource> : tensor<2xui32>
diff --git a/mlir/test/Bytecode/versioning/versioned_attr.mlir b/mlir/test/Bytecode/versioning/versioned_attr.mlir
--- a/mlir/test/Bytecode/versioning/versioned_attr.mlir
+++ b/mlir/test/Bytecode/versioning/versioned_attr.mlir
@@ -1,9 +1,6 @@
 // This file contains a test case representative of a dialect parsing an
 // attribute with versioned custom encoding.
 
-// Bytecode currently does not support big-endian platforms
-// UNSUPPORTED: target=s390x-{{.*}}
-
 //===--------------------------------------------------------------------===//
 // Test attribute upgrade
 //===--------------------------------------------------------------------===//
diff --git a/mlir/test/Bytecode/versioning/versioned_bytecode.mlir b/mlir/test/Bytecode/versioning/versioned_bytecode.mlir
--- a/mlir/test/Bytecode/versioning/versioned_bytecode.mlir
+++ b/mlir/test/Bytecode/versioning/versioned_bytecode.mlir
@@ -1,8 +1,5 @@
 // This file contains test cases related to roundtripping.
 
-// Bytecode currently does not support big-endian platforms
-// UNSUPPORTED: target=s390x-{{.*}}
-
 //===--------------------------------------------------------------------===//
 // Test roundtrip
 //===--------------------------------------------------------------------===//
diff --git a/mlir/test/Bytecode/versioning/versioned_op.mlir b/mlir/test/Bytecode/versioning/versioned_op.mlir
--- a/mlir/test/Bytecode/versioning/versioned_op.mlir
+++ b/mlir/test/Bytecode/versioning/versioned_op.mlir
@@ -1,9 +1,6 @@
 // This file contains test cases related to the dialect post-parsing upgrade
 // mechanism.
 
-// Bytecode currently does not support big-endian platforms
-// UNSUPPORTED: target=s390x-{{.*}}
-
 //===--------------------------------------------------------------------===//
 // Test generic
 //===--------------------------------------------------------------------===//
diff --git a/mlir/test/Dialect/Builtin/Bytecode/attrs.mlir b/mlir/test/Dialect/Builtin/Bytecode/attrs.mlir
--- a/mlir/test/Dialect/Builtin/Bytecode/attrs.mlir
+++ b/mlir/test/Dialect/Builtin/Bytecode/attrs.mlir
@@ -1,8 +1,5 @@
 // RUN: mlir-opt -emit-bytecode -allow-unregistered-dialect %s | mlir-opt -allow-unregistered-dialect -mlir-print-local-scope | FileCheck %s
 
-// Bytecode currently does not support big-endian platforms
-// UNSUPPORTED: target=s390x-{{.*}}
-
 //===----------------------------------------------------------------------===//
 // ArrayAttr
 //===----------------------------------------------------------------------===//
diff --git a/mlir/test/Dialect/Builtin/Bytecode/types.mlir b/mlir/test/Dialect/Builtin/Bytecode/types.mlir
--- a/mlir/test/Dialect/Builtin/Bytecode/types.mlir
+++ b/mlir/test/Dialect/Builtin/Bytecode/types.mlir
@@ -1,8 +1,5 @@
 // RUN: mlir-opt -emit-bytecode %s | mlir-opt | FileCheck %s
 
-// Bytecode currently does not support big-endian platforms
-// UNSUPPORTED: target=s390x-{{.*}}
-
 //===----------------------------------------------------------------------===//
 // ComplexType
 //===----------------------------------------------------------------------===//
diff --git a/mlir/test/Dialect/Quant/Bytecode/types.mlir b/mlir/test/Dialect/Quant/Bytecode/types.mlir
--- a/mlir/test/Dialect/Quant/Bytecode/types.mlir
+++ b/mlir/test/Dialect/Quant/Bytecode/types.mlir
@@ -1,8 +1,5 @@
 // RUN: mlir-opt -emit-bytecode %s | mlir-opt | FileCheck %s
 
-// Bytecode currently does not support big-endian platforms
-// UNSUPPORTED: target=s390x-{{.*}}
-
 //===----------------------------------------------------------------------===//
 // AnyQuantized
 //===----------------------------------------------------------------------===//
diff --git a/mlir/unittests/Bytecode/BytecodeTest.cpp b/mlir/unittests/Bytecode/BytecodeTest.cpp
--- a/mlir/unittests/Bytecode/BytecodeTest.cpp
+++ b/mlir/unittests/Bytecode/BytecodeTest.cpp
@@ -15,6 +15,7 @@
 #include "mlir/Parser/Parser.h"
 
 #include "llvm/ADT/StringRef.h"
+#include "llvm/Support/Endian.h"
 #include "gmock/gmock.h"
 #include "gtest/gtest.h"
 
@@ -54,6 +55,12 @@
       parseSourceString<Operation *>(ostream.str(), parseConfig);
   ASSERT_TRUE(roundTripModule);
 
+  // FIXME: Parsing external resources does not work on big-endian
+  // platforms currently.
+  if (llvm::support::endian::system_endianness() ==
+      llvm::support::endianness::big)
+    GTEST_SKIP();
+
   // Try to see if we have a valid resource in the parsed module.
   auto checkResourceAttribute = [&](Operation *op) {
     Attribute attr = roundTripModule->getAttr("bytecode.test");