diff --git a/mlir/include/mlir/Dialect/OpenACC/OpenACCOps.td b/mlir/include/mlir/Dialect/OpenACC/OpenACCOps.td
--- a/mlir/include/mlir/Dialect/OpenACC/OpenACCOps.td
+++ b/mlir/include/mlir/Dialect/OpenACC/OpenACCOps.td
@@ -656,7 +656,7 @@
                        UnitAttr:$asyncAttr,
                        Variadic<IntOrIndex>:$waitOperands,
                        UnitAttr:$waitAttr,
-                       Optional<IntOrIndex>:$numGangs,
+                       Variadic<IntOrIndex>:$numGangs,
                        Optional<IntOrIndex>:$numWorkers,
                        Optional<IntOrIndex>:$vectorLength,
                        Optional<I1>:$ifCond,
@@ -802,7 +802,7 @@
                        UnitAttr:$asyncAttr,
                        Variadic<IntOrIndex>:$waitOperands,
                        UnitAttr:$waitAttr,
-                       Optional<IntOrIndex>:$numGangs,
+                       Variadic<IntOrIndex>:$numGangs,
                        Optional<IntOrIndex>:$numWorkers,
                        Optional<IntOrIndex>:$vectorLength,
                        Optional<I1>:$ifCond,
diff --git a/mlir/lib/Dialect/OpenACC/IR/OpenACC.cpp b/mlir/lib/Dialect/OpenACC/IR/OpenACC.cpp
--- a/mlir/lib/Dialect/OpenACC/IR/OpenACC.cpp
+++ b/mlir/lib/Dialect/OpenACC/IR/OpenACC.cpp
@@ -573,7 +573,7 @@
 
 Value ParallelOp::getDataOperand(unsigned i) {
   unsigned numOptional = getAsync() ? 1 : 0;
-  numOptional += getNumGangs() ? 1 : 0;
+  numOptional += getNumGangs().size();
   numOptional += getNumWorkers() ? 1 : 0;
   numOptional += getVectorLength() ? 1 : 0;
   numOptional += getIfCond() ? 1 : 0;
@@ -590,6 +590,8 @@
           *this, getReductionRecipes(), getReductionOperands(), "reduction",
           "reductions", false)))
     return failure();
+  if (getNumGangs().size() > 3)
+    return emitOpError() << "num_gangs expects a maximum of 3 values";
   return checkDataOperands<acc::ParallelOp>(*this, getDataClauseOperands());
 }
 
@@ -631,12 +633,18 @@
 
 Value KernelsOp::getDataOperand(unsigned i) {
   unsigned numOptional = getAsync() ? 1 : 0;
+  numOptional += getWaitOperands().size();
+  numOptional += getNumGangs().size();
+  numOptional += getNumWorkers() ? 1 : 0;
+  numOptional += getVectorLength() ? 1 : 0;
   numOptional += getIfCond() ? 1 : 0;
   numOptional += getSelfCond() ? 1 : 0;
-  return getOperand(getWaitOperands().size() + numOptional + i);
+  return getOperand(numOptional + i);
 }
 
 LogicalResult acc::KernelsOp::verify() {
+  if (getNumGangs().size() > 3)
+    return emitOpError() << "num_gangs expects a maximum of 3 values";
   return checkDataOperands<acc::KernelsOp>(*this, getDataClauseOperands());
 }
 
diff --git a/mlir/test/Dialect/OpenACC/invalid.mlir b/mlir/test/Dialect/OpenACC/invalid.mlir
--- a/mlir/test/Dialect/OpenACC/invalid.mlir
+++ b/mlir/test/Dialect/OpenACC/invalid.mlir
@@ -486,3 +486,10 @@
   "test.openacc_dummy_op"() : () -> ()
   acc.yield
 }
+
+// -----
+
+%i64value = arith.constant 1 : i64
+// expected-error@+1 {{num_gangs expects a maximum of 3 values}}
+acc.parallel num_gangs(%i64value, %i64value, %i64value, %i64value : i64, i64, i64, i64) {
+}
diff --git a/mlir/test/Dialect/OpenACC/ops.mlir b/mlir/test/Dialect/OpenACC/ops.mlir
--- a/mlir/test/Dialect/OpenACC/ops.mlir
+++ b/mlir/test/Dialect/OpenACC/ops.mlir
@@ -443,6 +443,8 @@
   }
   acc.parallel num_gangs(%idxValue: index) {
   }
+  acc.parallel num_gangs(%i64value, %i64value, %idxValue : i64, i64, index) {
+  }
   acc.parallel num_workers(%i64value: i64) {
   }
   acc.parallel num_workers(%i32value: i32) {
@@ -494,6 +496,8 @@
 // CHECK-NEXT: }
 // CHECK:      acc.parallel num_gangs([[IDXVALUE]] : index) {
 // CHECK-NEXT: }
+// CHECK:      acc.parallel num_gangs([[I64VALUE]], [[I64VALUE]], [[IDXVALUE]] : i64, i64, index) {
+// CHECK-NEXT: }
 // CHECK:      acc.parallel num_workers([[I64VALUE]] : i64) {
 // CHECK-NEXT: }
 // CHECK:      acc.parallel num_workers([[I32VALUE]] : i32) {