Index: flang/lib/Semantics/check-omp-structure.h
===================================================================
--- flang/lib/Semantics/check-omp-structure.h
+++ flang/lib/Semantics/check-omp-structure.h
@@ -76,6 +76,10 @@
 static OmpDirectiveSet nestedOrderedErrSet{Directive::OMPD_critical,
     Directive::OMPD_ordered, Directive::OMPD_atomic, Directive::OMPD_task,
     Directive::OMPD_taskloop};
+static OmpDirectiveSet nestedBarrierErrSet{
+    OmpDirectiveSet{Directive::OMPD_critical, Directive::OMPD_ordered,
+        Directive::OMPD_atomic, Directive::OMPD_master} |
+    taskGeneratingSet | parallelSet | doSet};
 static OmpClauseSet privateSet{
     Clause::OMPC_private, Clause::OMPC_firstprivate, Clause::OMPC_lastprivate};
 static OmpClauseSet privateReductionSet{
@@ -199,6 +203,7 @@
   bool CheckReductionOperators(const parser::OmpClause::Reduction &);
   bool CheckIntrinsicOperator(
       const parser::DefinedOperator::IntrinsicOperator &);
+  void CheckBarrierNesting(const parser::OpenMPSimpleStandaloneConstruct &x);
   void CheckReductionTypeList(const parser::OmpClause::Reduction &);
   void CheckReductionArraySection(const parser::OmpObjectList &ompObjectList);
   void CheckIntentInPointerAndDefinable(
Index: flang/lib/Semantics/check-omp-structure.cpp
===================================================================
--- flang/lib/Semantics/check-omp-structure.cpp
+++ flang/lib/Semantics/check-omp-structure.cpp
@@ -492,10 +492,27 @@
   dirContext_.pop_back();
 }
 
+void OmpStructureChecker::CheckBarrierNesting(
+    const parser::OpenMPSimpleStandaloneConstruct &x) {
+  // A barrier region may not be `closely nested` inside a worksharing, loop,
+  // task, taskloop, critical, ordered, atomic, or master region.
+  // TODO:  Expand the check to include `LOOP` construct as well when it is
+  // supported.
+  if (GetContext().directive == llvm::omp::Directive::OMPD_barrier) {
+    if (IsCloselyNestedRegion(llvm::omp::nestedBarrierErrSet)) {
+      context_.Say(parser::FindSourceLocation(x),
+          "`BARRIER` region may not be closely nested inside of `WORKSHARING`, "
+          "`LOOP`, `TASK`, `TASKLOOP`,"
+          "`CRITICAL`, `ORDERED`, `ATOMIC` or `MASTER` region."_err_en_US);
+    }
+  }
+}
+
 void OmpStructureChecker::Enter(
     const parser::OpenMPSimpleStandaloneConstruct &x) {
   const auto &dir{std::get<parser::OmpSimpleStandaloneDirective>(x.t)};
   PushContextAndClauseSets(dir.source, dir.v);
+  CheckBarrierNesting(x);
 }
 
 void OmpStructureChecker::Leave(
Index: flang/test/Semantics/omp-nested-barrier.f90
===================================================================
--- /dev/null
+++ flang/test/Semantics/omp-nested-barrier.f90
@@ -0,0 +1,160 @@
+! RUN: %S/test_errors.sh %s %t %flang_fc1 -fopenmp
+! OpenMP Version 4.5
+! Various checks with the nesting of BARRIER construct
+
+program omp_nest_barrier
+  integer i, k, j
+  k = 0;
+
+  !$omp do
+  do i = 1, 10
+    k = k + 1
+    !ERROR: `BARRIER` region may not be closely nested inside of `WORKSHARING`, `LOOP`, `TASK`, `TASKLOOP`,`CRITICAL`, `ORDERED`, `ATOMIC` or `MASTER` region.
+    !$omp barrier
+    j = j -1
+  end do
+
+  !$omp do simd
+  do i = 1, 10
+    k = k + 1
+    !ERROR: `BARRIER` region may not be closely nested inside of `WORKSHARING`, `LOOP`, `TASK`, `TASKLOOP`,`CRITICAL`, `ORDERED`, `ATOMIC` or `MASTER` region.
+    !$omp barrier
+    j = j -1
+  end do
+
+  !$omp parallel do
+  do i = 1, 10
+    k = k + 1
+    !ERROR: `BARRIER` region may not be closely nested inside of `WORKSHARING`, `LOOP`, `TASK`, `TASKLOOP`,`CRITICAL`, `ORDERED`, `ATOMIC` or `MASTER` region.
+    !$omp barrier
+    j = j -1
+  end do
+
+  !$omp parallel do simd
+  do i = 1, 10
+    k = k + 1
+    !ERROR: `BARRIER` region may not be closely nested inside of `WORKSHARING`, `LOOP`, `TASK`, `TASKLOOP`,`CRITICAL`, `ORDERED`, `ATOMIC` or `MASTER` region.
+    !$omp barrier
+    j = j -1
+  end do
+
+  !$omp parallel
+  do i = 1, 10
+    k = k + 1
+    !ERROR: `BARRIER` region may not be closely nested inside of `WORKSHARING`, `LOOP`, `TASK`, `TASKLOOP`,`CRITICAL`, `ORDERED`, `ATOMIC` or `MASTER` region.
+    !$omp barrier
+    j = j -1
+  end do
+  !$omp end parallel
+
+  !$omp task
+  do i = 1, 10
+    k = k + 1
+    !ERROR: `BARRIER` region may not be closely nested inside of `WORKSHARING`, `LOOP`, `TASK`, `TASKLOOP`,`CRITICAL`, `ORDERED`, `ATOMIC` or `MASTER` region.
+    !$omp barrier
+    j = j -1
+  end do
+  !$omp end task
+
+  !$omp taskloop
+  do i = 1, 10
+    k = k + 1
+    !ERROR: `BARRIER` region may not be closely nested inside of `WORKSHARING`, `LOOP`, `TASK`, `TASKLOOP`,`CRITICAL`, `ORDERED`, `ATOMIC` or `MASTER` region.
+    !$omp barrier
+    j = j -1
+  end do
+  !$omp end taskloop
+
+  !$omp critical
+  do i = 1, 10
+    k = k + 1
+    !ERROR: `BARRIER` region may not be closely nested inside of `WORKSHARING`, `LOOP`, `TASK`, `TASKLOOP`,`CRITICAL`, `ORDERED`, `ATOMIC` or `MASTER` region.
+    !$omp barrier
+    j = j -1
+  end do
+  !$omp end critical
+
+  !$omp master
+  do i = 1, 10
+    k = k + 1
+    !ERROR: `BARRIER` region may not be closely nested inside of `WORKSHARING`, `LOOP`, `TASK`, `TASKLOOP`,`CRITICAL`, `ORDERED`, `ATOMIC` or `MASTER` region.
+    !$omp barrier
+    j = j -1
+  end do
+  !$omp end master
+
+  !$omp ordered
+  do i = 1, 10
+    k = k + 1
+    !ERROR: `BARRIER` region may not be closely nested inside of `WORKSHARING`, `LOOP`, `TASK`, `TASKLOOP`,`CRITICAL`, `ORDERED`, `ATOMIC` or `MASTER` region.
+    !$omp barrier
+    j = j -1
+  end do
+  !$omp end ordered
+
+  !$omp ordered
+  do i = 1, 10
+    !$omp distribute
+    do k =1, 10
+      print *, "hello"
+      !ERROR: `BARRIER` region may not be closely nested inside of `WORKSHARING`, `LOOP`, `TASK`, `TASKLOOP`,`CRITICAL`, `ORDERED`, `ATOMIC` or `MASTER` region.
+      !$omp barrier
+      j = j -1
+    end do
+    !$omp end distribute
+  end do
+  !$omp end ordered
+
+  !$omp master
+  do i = 1, 10
+    !$omp distribute
+    do k =1, 10
+      print *, "hello"
+      !ERROR: `BARRIER` region may not be closely nested inside of `WORKSHARING`, `LOOP`, `TASK`, `TASKLOOP`,`CRITICAL`, `ORDERED`, `ATOMIC` or `MASTER` region.
+      !$omp barrier
+      j = j -1
+    end do
+    !$omp end distribute
+  end do
+  !$omp end master
+
+  !$omp critical
+  do i = 1, 10
+    !$omp distribute
+    do k =1, 10
+      print *, "hello"
+      !ERROR: `BARRIER` region may not be closely nested inside of `WORKSHARING`, `LOOP`, `TASK`, `TASKLOOP`,`CRITICAL`, `ORDERED`, `ATOMIC` or `MASTER` region.
+      !$omp barrier
+      j = j -1
+    end do
+    !$omp end distribute
+  end do
+  !$omp end critical
+
+  !$omp taskloop
+  do i = 1, 10
+    !$omp distribute
+    do k =1, 10
+      print *, "hello"
+      !ERROR: `BARRIER` region may not be closely nested inside of `WORKSHARING`, `LOOP`, `TASK`, `TASKLOOP`,`CRITICAL`, `ORDERED`, `ATOMIC` or `MASTER` region.
+      !$omp barrier
+      j = j -1
+    end do
+    !$omp end distribute
+  end do
+  !$omp end taskloop
+
+  !$omp task
+  do i = 1, 10
+    !$omp distribute
+    do k =1, 10
+      print *, "hello"
+      !ERROR: `BARRIER` region may not be closely nested inside of `WORKSHARING`, `LOOP`, `TASK`, `TASKLOOP`,`CRITICAL`, `ORDERED`, `ATOMIC` or `MASTER` region.
+      !$omp barrier
+      j = j -1
+    end do
+    !$omp end distribute
+  end do
+  !$omp end task
+
+end program omp_nest_barrier