diff --git a/openmp/runtime/test/atomic/omp-atomic-compare-signedness.c b/openmp/runtime/test/atomic/omp-atomic-compare-signedness.c
--- a/openmp/runtime/test/atomic/omp-atomic-compare-signedness.c
+++ b/openmp/runtime/test/atomic/omp-atomic-compare-signedness.c
@@ -6,6 +6,10 @@
 // RUN: %libomp-compile -fopenmp-version=51
 // RUN: %libomp-run | FileCheck %s
 
+// This test uses -fopenmp-version, which is not a compiler flag that GCC
+// supports.
+// UNSUPPORTED: gcc
+
 // High parallelism increases our chances of detecting a lack of atomicity.
 #define NUM_THREADS_TRY 256
 
diff --git a/openmp/runtime/test/teams/teams-atomic.c b/openmp/runtime/test/teams/teams-atomic.c
--- a/openmp/runtime/test/teams/teams-atomic.c
+++ b/openmp/runtime/test/teams/teams-atomic.c
@@ -2,6 +2,8 @@
 // omp teams.  This is an extension to OpenMP 5.2 and is enabled by default.
 
 // RUN: %libomp-compile-and-run | FileCheck %s
+// GCC has really limited OpenMP 5.2 support yet.
+// UNSUPPORTED: gcc
 
 #include <omp.h>
 #include <stdbool.h>