diff --git a/mlir/include/mlir/Dialect/Async/CMakeLists.txt b/mlir/include/mlir/Dialect/Async/CMakeLists.txt
new file mode 100644
--- /dev/null
+++ b/mlir/include/mlir/Dialect/Async/CMakeLists.txt
@@ -0,0 +1 @@
+add_subdirectory(IR)
diff --git a/mlir/include/mlir/Dialect/Async/IR/Async.h b/mlir/include/mlir/Dialect/Async/IR/Async.h
new file mode 100644
--- /dev/null
+++ b/mlir/include/mlir/Dialect/Async/IR/Async.h
@@ -0,0 +1,39 @@
+//===- Async.h - MLIR Async dialect -----------------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This file defines the async dialect that is used for modeling asynchronous
+// execution.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef MLIR_DIALECT_ASYNC_IR_ASYNC_H
+#define MLIR_DIALECT_ASYNC_IR_ASYNC_H
+
+#include "mlir/IR/Dialect.h"
+#include "mlir/IR/OpDefinition.h"
+#include "mlir/IR/OpImplementation.h"
+#include "mlir/Interfaces/SideEffectInterfaces.h"
+
+namespace mlir {
+namespace async {
+
+/// The token type to represent asynchronous operation completion.
+class TokenType : public Type::TypeBase<TokenType, Type, TypeStorage> {
+public:
+  using Base::Base;
+};
+
+} // namespace async
+} // namespace mlir
+
+#define GET_OP_CLASSES
+#include "mlir/Dialect/Async/IR/AsyncOps.h.inc"
+
+#include "mlir/Dialect/Async/IR/AsyncOpsDialect.h.inc"
+
+#endif // MLIR_DIALECT_ASYNC_IR_ASYNC_H
diff --git a/mlir/include/mlir/Dialect/Async/IR/AsyncBase.td b/mlir/include/mlir/Dialect/Async/IR/AsyncBase.td
new file mode 100644
--- /dev/null
+++ b/mlir/include/mlir/Dialect/Async/IR/AsyncBase.td
@@ -0,0 +1,43 @@
+//===- AsyncBase.td ----------------------------------------*- tablegen -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// Base definitions for the `async` dialect.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef ASYNC_BASE_TD
+#define ASYNC_BASE_TD
+
+include "mlir/IR/OpBase.td"
+
+//===----------------------------------------------------------------------===//
+// Async dialect definitions
+//===----------------------------------------------------------------------===//
+
+def AsyncDialect : Dialect {
+  let name = "async";
+
+  let summary = "Types and operations for async dialect";
+  let description = [{
+    This dialect contains operations for modeling asynchronous execution.
+  }];
+
+  let cppNamespace = "::mlir::async";
+}
+
+def Async_TokenType : DialectType<AsyncDialect,
+    CPred<"$_self.isa<::mlir::async::TokenType>()">, "token type">,
+    BuildableType<"$_builder.getType<::mlir::async::TokenType>()"> {
+  let typeDescription = [{
+    `async.token` is a type returned by asynchronous operations, and it
+    becomes `ready` when the asyncrhonous oeprations that created it is
+    completed.
+  }];
+}
+
+#endif // ASYNC_BASE_TD
diff --git a/mlir/include/mlir/Dialect/Async/IR/AsyncOps.td b/mlir/include/mlir/Dialect/Async/IR/AsyncOps.td
new file mode 100644
--- /dev/null
+++ b/mlir/include/mlir/Dialect/Async/IR/AsyncOps.td
@@ -0,0 +1,76 @@
+//===- AsyncOps.td - Async operations definition -----------*- tablegen -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This is the operation definition file for Async dialect operations.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef ASYNC_OPS
+#define ASYNC_OPS
+
+include "mlir/Dialect/Async/IR/AsyncBase.td"
+include "mlir/Interfaces/SideEffectInterfaces.td"
+
+//===----------------------------------------------------------------------===//
+// Async op definitions
+//===----------------------------------------------------------------------===//
+
+// Base class for the operation in this dialect
+class Async_Op<string mnemonic, list<OpTrait> traits = []> :
+    Op<AsyncDialect, mnemonic, traits>;
+
+def Async_RegionOp : Async_Op<"region"> {
+  let summary = "Asynchronous region operation";
+  let description = [{
+    The `body` region attached to the `async.region` operation semantically
+    can be executed concurrently with the successor operation. In the followup
+    example "compute0" can be executed concurrently with "compute1".
+
+    The actual concurrency semantics depends on the dialect lowering to the
+    executable format. Fully sequential execution ("compute0" completes before
+    "compute1" starts) is a completely legal execution.
+
+    Because concurrent execution is not guaranteed, it is illegal to create an
+    implicit dependency from "compute1" to "compute0" (e.g. via shared global
+    state). All dependencies must be made explicit with async region arguments
+    (`async.token` or `async.value`).
+
+    Example:
+
+    ```mlir
+    %0 = async.region {
+      "compute0"(...)
+      async.yield
+    } : () -> !async.token
+
+    %1 = "compute1"(...)
+    ```
+  }];
+
+  // TODO: Take async.tokens/async.values as arguments.
+  let arguments = (ins );
+  let results = (outs Async_TokenType:$done);
+  let regions = (region SizedRegion<1>:$body);
+
+  let assemblyFormat = "$body attr-dict `:` `(` `)` `->` type($done)";
+}
+
+def Async_YieldOp :
+    Async_Op<"yield", [HasParent<"RegionOp">, NoSideEffect, Terminator]> {
+  let summary = "terminator for Async region operation";
+  let description = [{
+    The `async.yield` is a special terminator operation for the block inside
+    `async.region` operation.
+  }];
+
+  let arguments = (ins Variadic<AnyType>:$operands);
+
+  let assemblyFormat = "attr-dict ($operands^ `:` type($operands))?";
+}
+
+#endif // ASYNC_OPS
diff --git a/mlir/include/mlir/Dialect/Async/IR/CMakeLists.txt b/mlir/include/mlir/Dialect/Async/IR/CMakeLists.txt
new file mode 100644
--- /dev/null
+++ b/mlir/include/mlir/Dialect/Async/IR/CMakeLists.txt
@@ -0,0 +1,2 @@
+add_mlir_dialect(AsyncOps async)
+add_mlir_doc(AsyncOps -gen-dialect-doc AsyncDialect Dialects/)
diff --git a/mlir/include/mlir/Dialect/CMakeLists.txt b/mlir/include/mlir/Dialect/CMakeLists.txt
--- a/mlir/include/mlir/Dialect/CMakeLists.txt
+++ b/mlir/include/mlir/Dialect/CMakeLists.txt
@@ -1,4 +1,5 @@
 add_subdirectory(Affine)
+add_subdirectory(Async)
 add_subdirectory(AVX512)
 add_subdirectory(GPU)
 add_subdirectory(Linalg)
diff --git a/mlir/include/mlir/InitAllDialects.h b/mlir/include/mlir/InitAllDialects.h
--- a/mlir/include/mlir/InitAllDialects.h
+++ b/mlir/include/mlir/InitAllDialects.h
@@ -16,6 +16,7 @@
 
 #include "mlir/Dialect/AVX512/AVX512Dialect.h"
 #include "mlir/Dialect/Affine/IR/AffineOps.h"
+#include "mlir/Dialect/Async/IR/Async.h"
 #include "mlir/Dialect/GPU/GPUDialect.h"
 #include "mlir/Dialect/LLVMIR/LLVMAVX512Dialect.h"
 #include "mlir/Dialect/LLVMIR/LLVMDialect.h"
@@ -42,6 +43,7 @@
   // clang-format off
   registry.insert<acc::OpenACCDialect,
                   AffineDialect,
+                  async::AsyncDialect,
                   avx512::AVX512Dialect,
                   gpu::GPUDialect,
                   LLVM::LLVMAVX512Dialect,
diff --git a/mlir/lib/Dialect/Async/CMakeLists.txt b/mlir/lib/Dialect/Async/CMakeLists.txt
new file mode 100644
--- /dev/null
+++ b/mlir/lib/Dialect/Async/CMakeLists.txt
@@ -0,0 +1 @@
+add_subdirectory(IR)
diff --git a/mlir/lib/Dialect/Async/IR/Async.cpp b/mlir/lib/Dialect/Async/IR/Async.cpp
new file mode 100644
--- /dev/null
+++ b/mlir/lib/Dialect/Async/IR/Async.cpp
@@ -0,0 +1,54 @@
+//===- Async.cpp - MLIR Async Operations ----------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "mlir/Dialect/Async/IR/Async.h"
+
+#include "mlir/Dialect/StandardOps/IR/Ops.h"
+#include "mlir/Dialect/Traits.h"
+#include "mlir/IR/Builders.h"
+#include "mlir/IR/DialectImplementation.h"
+#include "mlir/IR/PatternMatch.h"
+#include "mlir/IR/StandardTypes.h"
+#include "mlir/Transforms/InliningUtils.h"
+#include "llvm/ADT/SmallString.h"
+#include "llvm/ADT/TypeSwitch.h"
+#include "llvm/Support/raw_ostream.h"
+
+using namespace mlir;
+using namespace mlir::async;
+
+void AsyncDialect::initialize() {
+  addOperations<
+#define GET_OP_LIST
+#include "mlir/Dialect/Async/IR/AsyncOps.cpp.inc"
+      >();
+  addTypes<TokenType>();
+}
+
+/// Parse a type registered to this dialect.
+Type AsyncDialect::parseType(DialectAsmParser &parser) const {
+  StringRef keyword;
+  if (parser.parseKeyword(&keyword))
+    return Type();
+
+  if (keyword == "token")
+    return TokenType::get(getContext());
+
+  parser.emitError(parser.getNameLoc(), "unknown async type: ") << keyword;
+  return Type();
+}
+
+/// Print a type registered to this dialect.
+void AsyncDialect::printType(Type type, DialectAsmPrinter &os) const {
+  TypeSwitch<Type>(type)
+      .Case<TokenType>([&](Type) { os << "token"; })
+      .Default([](Type) { llvm_unreachable("unexpected 'async' type kind"); });
+}
+
+#define GET_OP_CLASSES
+#include "mlir/Dialect/Async/IR/AsyncOps.cpp.inc"
diff --git a/mlir/lib/Dialect/Async/IR/CMakeLists.txt b/mlir/lib/Dialect/Async/IR/CMakeLists.txt
new file mode 100644
--- /dev/null
+++ b/mlir/lib/Dialect/Async/IR/CMakeLists.txt
@@ -0,0 +1,13 @@
+add_mlir_dialect_library(MLIRAsync
+  Async.cpp
+
+  ADDITIONAL_HEADER_DIRS
+  ${MLIR_MAIN_INCLUDE_DIR}/mlir/Dialect/Async
+
+  DEPENDS
+  MLIRAsyncOpsIncGen
+
+  LINK_LIBS PUBLIC
+  MLIRDialect
+  MLIRIR
+  )
diff --git a/mlir/lib/Dialect/CMakeLists.txt b/mlir/lib/Dialect/CMakeLists.txt
--- a/mlir/lib/Dialect/CMakeLists.txt
+++ b/mlir/lib/Dialect/CMakeLists.txt
@@ -1,4 +1,5 @@
 add_subdirectory(Affine)
+add_subdirectory(Async)
 add_subdirectory(AVX512)
 add_subdirectory(GPU)
 add_subdirectory(Linalg)
diff --git a/mlir/test/Dialect/Async/ops.mlir b/mlir/test/Dialect/Async/ops.mlir
new file mode 100644
--- /dev/null
+++ b/mlir/test/Dialect/Async/ops.mlir
@@ -0,0 +1,16 @@
+// RUN: mlir-opt  %s | FileCheck %s
+
+// CHECK-LABEL: @identity
+func @identity(%arg0 : !async.token) -> !async.token {
+  // CHECK: return %arg0 : !async.token
+  return %arg0 : !async.token
+}
+
+// CHECK-LABEL: @empty_async_region
+func @empty_async_region() -> !async.token {
+  %0 = async.region {
+    async.yield
+  } : () -> !async.token
+
+  return %0 : !async.token
+}