diff --git a/flang/lib/Lower/OpenMP.cpp b/flang/lib/Lower/OpenMP.cpp
--- a/flang/lib/Lower/OpenMP.cpp
+++ b/flang/lib/Lower/OpenMP.cpp
@@ -75,6 +75,36 @@
       standaloneConstruct.u);
 }
 
+static void
+genOMP(Fortran::lower::AbstractConverter &absConv,
+       Fortran::lower::pft::Evaluation &eval,
+       const Fortran::parser::OpenMPBlockConstruct &blockConstruct) {
+  const auto &blockDirective =
+      std::get<Fortran::parser::OmpBeginBlockDirective>(blockConstruct.t);
+  const auto &parallelDirective =
+      std::get<Fortran::parser::OmpBlockDirective>(blockDirective.t);
+  if (parallelDirective.v == llvm::omp::OMPD_parallel) {
+    auto &firOpBuilder = absConv.getFirOpBuilder();
+    auto currentLocation = absConv.getCurrentLocation();
+    auto insertPt = firOpBuilder.saveInsertionPoint();
+    llvm::ArrayRef<mlir::Type> argTy;
+    mlir::ValueRange range;
+    llvm::SmallVector<int32_t, 6> operandSegmentSizes(6 /*Size=*/,
+                                                      0 /*Value=*/);
+    // create and insert the operation.
+    auto parallelOp = firOpBuilder.create<mlir::omp::ParallelOp>(
+        currentLocation, argTy, range);
+    parallelOp.setAttr(mlir::omp::ParallelOp::getOperandSegmentSizeAttr(),
+                       firOpBuilder.getI32VectorAttr(operandSegmentSizes));
+    parallelOp.getRegion().push_back(new Block{});
+    auto &block = parallelOp.getRegion().back();
+    firOpBuilder.setInsertionPointToStart(&block);
+    // ensure the block is well-formed.
+    firOpBuilder.create<mlir::omp::TerminatorOp>(currentLocation);
+    firOpBuilder.restoreInsertionPoint(insertPt);
+  }
+}
+
 void Fortran::lower::genOpenMPConstruct(
     Fortran::lower::AbstractConverter &absConv,
     Fortran::lower::pft::Evaluation &eval,
@@ -92,7 +122,7 @@
             TODO();
           },
           [&](const Fortran::parser::OpenMPBlockConstruct &blockConstruct) {
-            TODO();
+            genOMP(absConv, eval, blockConstruct);
           },
           [&](const Fortran::parser::OpenMPAtomicConstruct &atomicConstruct) {
             TODO();
diff --git a/flang/unittests/Lower/OpenMPLoweringTest.cpp b/flang/unittests/Lower/OpenMPLoweringTest.cpp
--- a/flang/unittests/Lower/OpenMPLoweringTest.cpp
+++ b/flang/unittests/Lower/OpenMPLoweringTest.cpp
@@ -71,4 +71,31 @@
   EXPECT_EQ(succeeded(taskYieldOp.verify()), true);
 }
 
+TEST_F(OpenMPLoweringTest, EmptyParallel) {
+  // Construct a dummy parse tree node for `!OMP parallel`.
+  struct Fortran::parser::OmpSimpleStandaloneDirective parallelDirective(
+      llvm::omp::Directive::OMPD_parallel);
+
+  // Check and lower the `!OMP parallel` node to `ParallelOp` operation of
+  // OpenMPDialect.
+  EXPECT_EQ(parallelDirective.v, llvm::omp::Directive::OMPD_parallel);
+  auto insertPt = mlirOpBuilder->saveInsertionPoint();
+  llvm::ArrayRef<mlir::Type> argTy;
+  mlir::ValueRange range;
+  llvm::SmallVector<int32_t, 6> operandSegmentSizes(6 /*Size=*/, 0 /*Value=*/);
+  // create and insert the operation.
+  auto parallelOp = mlirOpBuilder->create<mlir::omp::ParallelOp>(
+      mlirOpBuilder->getUnknownLoc(), argTy, range);
+  parallelOp.setAttr(mlir::omp::ParallelOp::getOperandSegmentSizeAttr(),
+      mlirOpBuilder->getI32VectorAttr(operandSegmentSizes));
+  parallelOp.getRegion().push_back(new mlir::Block{});
+  auto &block = parallelOp.getRegion().back();
+  mlirOpBuilder->setInsertionPointToStart(&block);
+  // ensure the block is well-formed.
+  mlirOpBuilder->create<mlir::omp::TerminatorOp>(
+      mlirOpBuilder->getUnknownLoc());
+  mlirOpBuilder->restoreInsertionPoint(insertPt);
+  EXPECT_EQ(succeeded(parallelOp.verify()), true);
+}
+
 // main() from gtest_main