diff --git a/mlir/include/mlir/Dialect/Vector/IR/VectorOps.td b/mlir/include/mlir/Dialect/Vector/IR/VectorOps.td
--- a/mlir/include/mlir/Dialect/Vector/IR/VectorOps.td
+++ b/mlir/include/mlir/Dialect/Vector/IR/VectorOps.td
@@ -2374,7 +2374,7 @@
     ```
   }];
 
-  // TODO: Support multiple results and passthru values.
+  // TODO: Support multiple passthru values.
   let arguments = (ins VectorOf<[I1]>:$mask,
                    Optional<AnyType>:$passthru);
   let results = (outs Variadic<AnyType>:$results);
@@ -2393,10 +2393,21 @@
 
   let extraClassDeclaration = [{
     Block *getMaskBlock() { return &getMaskRegion().front(); }
-    static void ensureTerminator(Region &region, Builder &builder, Location loc);
+
+    /// Returns true if mask op is not masking any operation.
+    bool isEmpty() {
+      Block *block = getMaskBlock();
+      if (block->getOperations().size() > 1)
+        return false;
+      return true;
+    }
+
+    static void ensureTerminator(Region &region, Builder &builder,
+                                 Location loc);
   }];
 
   let hasCanonicalizer = 1;
+  let hasFolder = 1;
   let hasCustomAssemblyFormat = 1;
   let hasVerifier = 1;
 }
diff --git a/mlir/lib/Dialect/Vector/IR/VectorOps.cpp b/mlir/lib/Dialect/Vector/IR/VectorOps.cpp
--- a/mlir/lib/Dialect/Vector/IR/VectorOps.cpp
+++ b/mlir/lib/Dialect/Vector/IR/VectorOps.cpp
@@ -5641,6 +5641,25 @@
   return success();
 }
 
+/// Folds vector.mask ops with an all-true mask.
+LogicalResult MaskOp::fold(FoldAdaptor adaptor,
+                           SmallVectorImpl<OpFoldResult> &results) {
+  MaskFormat maskFormat = getMaskFormat(getMask());
+  if (isEmpty())
+    return failure();
+
+  if (maskFormat != MaskFormat::AllTrue)
+    return failure();
+
+  // Move maskable operation outside of the `vector.mask` region.
+  Operation *maskableOp = getMaskableOp();
+  maskableOp->dropAllUses();
+  maskableOp->moveBefore(getOperation());
+
+  results.push_back(maskableOp->getResult(0));
+  return success();
+}
+
 // Elides empty vector.mask operations with or without return values. Propagates
 // the yielded values by the vector.yield terminator, if any, or erases the op,
 // otherwise.
@@ -5653,10 +5672,10 @@
     if (maskingOp.getMaskableOp())
       return failure();
 
-    Block *block = maskOp.getMaskBlock();
-    if (block->getOperations().size() > 1)
+    if (!maskOp.isEmpty())
       return failure();
 
+    Block *block = maskOp.getMaskBlock();
     auto terminator = cast<vector::YieldOp>(block->front());
     if (terminator.getNumOperands() == 0)
       rewriter.eraseOp(maskOp);
diff --git a/mlir/test/Dialect/Vector/canonicalize.mlir b/mlir/test/Dialect/Vector/canonicalize.mlir
--- a/mlir/test/Dialect/Vector/canonicalize.mlir
+++ b/mlir/test/Dialect/Vector/canonicalize.mlir
@@ -2257,4 +2257,16 @@
   return %0 : vector<8xf32>
 }
 
+// -----
+
+// CHECK-LABEL: func @all_true_vector_mask
+//  CHECK-SAME:     %[[IN:.*]]: vector<3x4xf32>
+func.func @all_true_vector_mask(%a : vector<3x4xf32>) -> vector<3x4xf32> {
+//   CHECK-NOT:   vector.mask
+//       CHECK:   %[[ADD:.*]] = arith.addf %[[IN]], %[[IN]] : vector<3x4xf32>
+//       CHECK:   return %[[ADD]] : vector<3x4xf32>
+  %all_true = vector.constant_mask [3, 4] : vector<3x4xi1>
+  %0 = vector.mask %all_true { arith.addf %a, %a : vector<3x4xf32> } : vector<3x4xi1> -> vector<3x4xf32>
+  return %0 : vector<3x4xf32>
+}