Index: flang/lib/Semantics/check-omp-structure.h
===================================================================
--- flang/lib/Semantics/check-omp-structure.h
+++ flang/lib/Semantics/check-omp-structure.h
@@ -194,6 +194,7 @@
   void CheckLoopItrVariableIsInt(const parser::OpenMPLoopConstruct &x);
   void CheckDoWhile(const parser::OpenMPLoopConstruct &x);
   void CheckCycleConstraints(const parser::OpenMPLoopConstruct &x);
+  void CheckSIMDNest(const parser::OpenMPConstruct &x);
   std::int64_t GetOrdCollapseLevel(const parser::OpenMPLoopConstruct &x);
   void CheckIfDoOrderedClause(const parser::OmpBlockDirective &blkDirectiv);
   bool CheckReductionOperators(const parser::OmpClause::Reduction &);
Index: flang/lib/Semantics/check-omp-structure.cpp
===================================================================
--- flang/lib/Semantics/check-omp-structure.cpp
+++ flang/lib/Semantics/check-omp-structure.cpp
@@ -141,8 +141,15 @@
   return false;
 }
 
-void OmpStructureChecker::Enter(const parser::OpenMPConstruct &) {
-  // 2.8.1 TODO: Simd Construct with Ordered Construct Nesting check
+void OmpStructureChecker::Enter(const parser::OpenMPConstruct &x) {
+  // Simd Construct with Ordered Construct Nesting check
+  // We cannot use CurrentDirectiveIsNested() here because
+  // PushContextAndClauseSets() has not been called yet, it is
+  // called individually for each construct.  Therefore a
+  // dirContext_ size `1` means the current construct is nested
+  if (dirContext_.size() == 1) {
+    CheckSIMDNest(x);
+  }
 }
 
 void OmpStructureChecker::Enter(const parser::OpenMPLoopConstruct &x) {
@@ -251,6 +258,45 @@
   }
 }
 
+void OmpStructureChecker::CheckSIMDNest(const parser::OpenMPConstruct &c) {
+  // Check if the parent context has the SIMD clause
+  // Please not that we use GetContext() instead of GetContextParent()
+  // because PushContextAndClauseSets() has not been called on the
+  // current context yet.
+  // TODO: Check for declare simd regions.
+  bool eligibleSIMD = false;
+  if (llvm::omp::simdSet.test(GetContext().directive)) {
+    std::visit(
+        Fortran::common::visitors{
+            [&](const parser::OpenMPBlockConstruct &c) {
+              // Allow `!$OMP ORDERED SIMD`
+              const auto &beginBlockDir{
+                  std::get<parser::OmpBeginBlockDirective>(c.t)};
+              const auto &clauses{
+                  std::get<parser::OmpClauseList>(beginBlockDir.t)};
+              for (const auto &clause : clauses.v) {
+                if (std::get_if<parser::OmpClause::Simd>(&clause.u)) {
+                  eligibleSIMD = true;
+                  break;
+                }
+              }
+            },
+            [&](const parser::OpenMPAtomicConstruct &c) {
+              // Allow `!$OMP ATOMIC`
+              eligibleSIMD = true;
+            },
+            [&](const auto &c) {},
+        },
+        c.u);
+    if (!eligibleSIMD) {
+      context_.Say(
+          parser::FindSourceLocation(c),
+          "OpenMP constructs other than `!$OMP ORDERED SIMD` or '!$OMP ATOMIC'"
+          " may not be nested inside 'SIMD' region."_err_en_US);
+    }
+  }
+}
+
 std::int64_t OmpStructureChecker::GetOrdCollapseLevel(
     const parser::OpenMPLoopConstruct &x) {
   const auto &beginLoopDir{std::get<parser::OmpBeginLoopDirective>(x.t)};
Index: flang/test/Semantics/omp-nested-simd.f90
===================================================================
--- /dev/null
+++ flang/test/Semantics/omp-nested-simd.f90
@@ -0,0 +1,206 @@
+! RUN: %S/test_errors.sh %s %t %flang_fc1 -fopenmp
+! OpenMP Version 4.5
+! Various checks with the nesting of SIMD construct
+
+SUBROUTINE NESTED_GOOD(N)
+  INTEGER N, I, J, K, A(10), B(10)
+  !$OMP SIMD
+  DO I = 1,N
+    !$OMP ATOMIC
+    K =  K + 1
+    IF (I <= 10) THEN
+      !$OMP ORDERED SIMD
+      DO J = 1,N
+        A(J) = J
+      END DO
+      !$OMP END ORDERED
+    ENDIF
+  END DO
+  !$OMP END SIMD
+END SUBROUTINE NESTED_GOOD
+
+SUBROUTINE NESTED_BAD(N)
+  INTEGER N, I, J, K, A(10), B(10)
+
+  !$OMP SIMD
+  DO I = 1,N
+    !$OMP ATOMIC
+    K =  K + 1
+    IF (I <= 10) THEN
+      !ERROR: OpenMP constructs other than `!$OMP ORDERED SIMD` or '!$OMP ATOMIC' may not be nested inside 'SIMD' region.
+      !$OMP SIMD
+      DO J = 1,N
+        A(J) = J
+      END DO
+      !$OMP END SIMD
+      !ERROR: OpenMP constructs other than `!$OMP ORDERED SIMD` or '!$OMP ATOMIC' may not be nested inside 'SIMD' region.
+      !$omp task 
+      do J = 1, N
+        K = 2
+      end do
+      !$omp end task
+      !ERROR: OpenMP constructs other than `!$OMP ORDERED SIMD` or '!$OMP ATOMIC' may not be nested inside 'SIMD' region.
+      !$omp teams 
+      do J = 1, N
+        K = 2
+      end do
+      !$omp end teams
+      !ERROR: OpenMP constructs other than `!$OMP ORDERED SIMD` or '!$OMP ATOMIC' may not be nested inside 'SIMD' region.
+      !$omp target 
+      do J = 1, N
+        K = 2
+      end do
+      !$omp end target
+      !ERROR: OpenMP constructs other than `!$OMP ORDERED SIMD` or '!$OMP ATOMIC' may not be nested inside 'SIMD' region.
+      !$OMP DO
+      DO J = 1,N
+        A(J) = J
+      END DO
+      !$OMP END DO
+      !ERROR: OpenMP constructs other than `!$OMP ORDERED SIMD` or '!$OMP ATOMIC' may not be nested inside 'SIMD' region.
+      !$OMP PARALLEL DO
+      DO J = 1,N
+        A(J) = J
+      END DO
+      !$OMP END PARALLEL DO
+    ENDIF
+  END DO
+  !$OMP END SIMD
+
+  !$OMP DO SIMD
+  DO I = 1,N
+    !$OMP ATOMIC
+    K =  K + 1
+    IF (I <= 10) THEN
+      !ERROR: OpenMP constructs other than `!$OMP ORDERED SIMD` or '!$OMP ATOMIC' may not be nested inside 'SIMD' region.
+      !$OMP SIMD
+      DO J = 1,N
+        A(J) = J
+      END DO
+      !$OMP END SIMD
+      !ERROR: OpenMP constructs other than `!$OMP ORDERED SIMD` or '!$OMP ATOMIC' may not be nested inside 'SIMD' region.
+      !$omp task 
+      do J = 1, N
+        K = 2
+      end do
+      !$omp end task
+      !ERROR: OpenMP constructs other than `!$OMP ORDERED SIMD` or '!$OMP ATOMIC' may not be nested inside 'SIMD' region.
+      !$omp teams 
+      do J = 1, N
+        K = 2
+      end do
+      !$omp end teams
+      !ERROR: OpenMP constructs other than `!$OMP ORDERED SIMD` or '!$OMP ATOMIC' may not be nested inside 'SIMD' region.
+      !$omp target 
+      do J = 1, N
+        K = 2
+      end do
+      !$omp end target
+      !ERROR: OpenMP constructs other than `!$OMP ORDERED SIMD` or '!$OMP ATOMIC' may not be nested inside 'SIMD' region.
+      !$OMP DO
+      DO J = 1,N
+        A(J) = J
+      END DO
+      !$OMP END DO
+      !ERROR: OpenMP constructs other than `!$OMP ORDERED SIMD` or '!$OMP ATOMIC' may not be nested inside 'SIMD' region.
+      !$OMP PARALLEL DO
+      DO J = 1,N
+        A(J) = J
+      END DO
+      !$OMP END PARALLEL DO
+    ENDIF
+  END DO
+  !$OMP END DO SIMD
+
+  !$OMP PARALLEL DO SIMD
+  DO I = 1,N
+    !$OMP ATOMIC
+    K =  K + 1
+    IF (I <= 10) THEN
+      !ERROR: OpenMP constructs other than `!$OMP ORDERED SIMD` or '!$OMP ATOMIC' may not be nested inside 'SIMD' region.
+      !$OMP SIMD
+      DO J = 1,N
+        A(J) = J
+      END DO
+      !$OMP END SIMD
+      !ERROR: OpenMP constructs other than `!$OMP ORDERED SIMD` or '!$OMP ATOMIC' may not be nested inside 'SIMD' region.
+      !$omp task 
+      do J = 1, N
+        K = 2
+      end do
+      !$omp end task
+      !ERROR: OpenMP constructs other than `!$OMP ORDERED SIMD` or '!$OMP ATOMIC' may not be nested inside 'SIMD' region.
+      !$omp teams 
+      do J = 1, N
+        K = 2
+      end do
+      !$omp end teams
+      !ERROR: OpenMP constructs other than `!$OMP ORDERED SIMD` or '!$OMP ATOMIC' may not be nested inside 'SIMD' region.
+      !$omp target 
+      do J = 1, N
+        K = 2
+      end do
+      !$omp end target
+      !ERROR: OpenMP constructs other than `!$OMP ORDERED SIMD` or '!$OMP ATOMIC' may not be nested inside 'SIMD' region.
+      !$OMP DO
+      DO J = 1,N
+        A(J) = J
+      END DO
+      !$OMP END DO
+      !ERROR: OpenMP constructs other than `!$OMP ORDERED SIMD` or '!$OMP ATOMIC' may not be nested inside 'SIMD' region.
+      !$OMP PARALLEL DO
+      DO J = 1,N
+        A(J) = J
+      END DO
+      !$OMP END PARALLEL DO
+    ENDIF
+  END DO
+  !$OMP END PARALLEL DO SIMD
+
+  !$OMP TARGET SIMD
+  DO I = 1,N
+    !$OMP ATOMIC
+    K =  K + 1
+    IF (I <= 10) THEN
+      !ERROR: OpenMP constructs other than `!$OMP ORDERED SIMD` or '!$OMP ATOMIC' may not be nested inside 'SIMD' region.
+      !$OMP SIMD
+      DO J = 1,N
+        A(J) = J
+      END DO
+      !$OMP END SIMD
+      !ERROR: OpenMP constructs other than `!$OMP ORDERED SIMD` or '!$OMP ATOMIC' may not be nested inside 'SIMD' region.
+      !$omp task 
+      do J = 1, N
+        K = 2
+      end do
+      !$omp end task
+      !ERROR: OpenMP constructs other than `!$OMP ORDERED SIMD` or '!$OMP ATOMIC' may not be nested inside 'SIMD' region.
+      !$omp teams 
+      do J = 1, N
+        K = 2
+      end do
+      !$omp end teams
+      !ERROR: OpenMP constructs other than `!$OMP ORDERED SIMD` or '!$OMP ATOMIC' may not be nested inside 'SIMD' region.
+      !$omp target 
+      do J = 1, N
+        K = 2
+      end do
+      !$omp end target
+      !ERROR: OpenMP constructs other than `!$OMP ORDERED SIMD` or '!$OMP ATOMIC' may not be nested inside 'SIMD' region.
+      !$OMP DO
+      DO J = 1,N
+        A(J) = J
+      END DO
+      !$OMP END DO
+      !ERROR: OpenMP constructs other than `!$OMP ORDERED SIMD` or '!$OMP ATOMIC' may not be nested inside 'SIMD' region.
+      !$OMP PARALLEL DO
+      DO J = 1,N
+        A(J) = J
+      END DO
+      !$OMP END PARALLEL DO
+    ENDIF
+  END DO
+  !$OMP END TARGET SIMD
+
+
+END SUBROUTINE NESTED_BAD
Index: flang/test/Semantics/omp-ordered-simd.f90
===================================================================
--- flang/test/Semantics/omp-ordered-simd.f90
+++ flang/test/Semantics/omp-ordered-simd.f90
@@ -22,17 +22,6 @@
 SUBROUTINE ORDERED_BAD(N)
   INTEGER N, I, A(10), B(10), C(10)
 
-  !$OMP DO SIMD
-  DO I = 1,N
-    IF (I <= 10) THEN
-      !ERROR: The ORDERED clause must be present on the loop construct if any ORDERED region ever binds to a loop region arising from the loop construct.
-      !$OMP ORDERED 
-      CALL WORK(I)
-      !$OMP END ORDERED
-    ENDIF
-  END DO
-  !$OMP END DO SIMD
-
   !$OMP PARALLEL DO
   DO I = 1,N
     IF (I <= 10) THEN