diff --git a/flang/test/Semantics/omp-parallel-default.f90 b/flang/test/Semantics/omp-parallel-default.f90
new file mode 100644
--- /dev/null
+++ b/flang/test/Semantics/omp-parallel-default.f90
@@ -0,0 +1,12 @@
+!RUN: %S/test_errors.sh %s %t %f18 -fopenmp
+! OpenMP Version 4.5
+! 2.15.3.1 default Clause
+program omp_parallel_default
+  integer :: a(10), b(10), c(10),i,k
+  !ERROR: At most one DEFAULT clause can appear on the PARALLEL directive
+  !$omp parallel default(shared), default(private)
+  do i = 1, 10
+    c(i) = a(i) + b(i) + k
+  end do
+  !$omp end parallel
+end program omp_parallel_default
diff --git a/flang/test/Semantics/omp-task-default.f90 b/flang/test/Semantics/omp-task-default.f90
new file mode 100644
--- /dev/null
+++ b/flang/test/Semantics/omp-task-default.f90
@@ -0,0 +1,12 @@
+!RUN: %S/test_errors.sh %s %t %f18 -fopenmp
+! OpenMP Version 4.5
+! 2.15.3.1 default Clause
+program omp_task_default
+  integer :: a(10), b(10), c(10),i,k
+  !ERROR: At most one DEFAULT clause can appear on the TASK directive
+  !$omp task default(shared), default(none),shared(a,b,c,k,i)
+  do i = 1, 10
+    c(i) = a(i) + b(i) + k
+  end do
+  !$omp end task
+end program omp_task_default
diff --git a/flang/test/Semantics/omp-taskloop-default.f90 b/flang/test/Semantics/omp-taskloop-default.f90
new file mode 100644
--- /dev/null
+++ b/flang/test/Semantics/omp-taskloop-default.f90
@@ -0,0 +1,12 @@
+!RUN: %S/test_errors.sh %s %t %f18 -fopenmp
+! OpenMP Version 4.5
+! 2.15.3.1 default Clause
+program omp_taskloop_default
+  integer :: a(10), b(10), c(10),i,k
+  !ERROR: At most one DEFAULT clause can appear on the TASKLOOP directive
+  !$omp taskloop default(shared), default(private)
+  do i = 1, 10
+    c(i) = a(i) + b(i) + k
+  end do
+  !$omp end taskloop
+end program omp_taskloop_default
diff --git a/flang/test/Semantics/omp-teams-default.f90 b/flang/test/Semantics/omp-teams-default.f90
new file mode 100644
--- /dev/null
+++ b/flang/test/Semantics/omp-teams-default.f90
@@ -0,0 +1,12 @@
+!RUN: %S/test_errors.sh %s %t %f18 -fopenmp
+! OpenMP Version 4.5
+! 2.15.3.1 default Clause
+program omp_teams_default
+  integer :: a(10), b(10), c(10),i,k
+  !ERROR: At most one DEFAULT clause can appear on the TEAMS directive
+  !$omp teams default(shared), default(none),shared(i,a,b,k,c)
+  do i = 1, 10
+    c(i) = a(i) + b(i) + k
+  end do
+  !$omp end teams
+end program omp_teams_default
diff --git a/llvm/include/llvm/Frontend/OpenMP/OMP.td b/llvm/include/llvm/Frontend/OpenMP/OMP.td
--- a/llvm/include/llvm/Frontend/OpenMP/OMP.td
+++ b/llvm/include/llvm/Frontend/OpenMP/OMP.td
@@ -306,6 +306,7 @@
     VersionedClause<OMPC_Allocate>
   ];
   let allowedOnceClauses = [
+    VersionedClause<OMPC_Default>,
     VersionedClause<OMPC_If>,
     VersionedClause<OMPC_NumThreads>,
     VersionedClause<OMPC_ProcBind>,
@@ -326,6 +327,7 @@
     VersionedClause<OMPC_Affinity, 50>
   ];
   let allowedOnceClauses = [
+    VersionedClause<OMPC_Default>,
     VersionedClause<OMPC_If>,
     VersionedClause<OMPC_Final>,
     VersionedClause<OMPC_Priority>
@@ -816,6 +818,7 @@
     VersionedClause<OMPC_Allocate>
   ];
   let allowedOnceClauses = [
+    VersionedClause<OMPC_Default>,
     VersionedClause<OMPC_If>,
     VersionedClause<OMPC_Collapse>,
     VersionedClause<OMPC_Final>,