diff --git a/aws-encryption-sdk-cpp/tests/test_vectors/static_test_vectors.cpp b/aws-encryption-sdk-cpp/tests/test_vectors/static_test_vectors.cpp
index f6c2fe3ee..9ab6549a9 100644
--- a/aws-encryption-sdk-cpp/tests/test_vectors/static_test_vectors.cpp
+++ b/aws-encryption-sdk-cpp/tests/test_vectors/static_test_vectors.cpp
@@ -34,6 +34,7 @@
 
 #include <json-c/json.h>
 #include <json-c/json_object.h>
+#include <unistd.h>
 
 #include "credential_reusing_client_supplier.h"
 #include "testing.h"
@@ -435,6 +436,14 @@ static int run_test_decryption(
     return result;
 }
 
+static void kms_delay(test_type test_type_idx) {
+    static int tenth_second_in_millis = 100;
+    if ((test_type_idx == AWS_CRYPTOSDK_KMS) || (test_type_idx == AWS_CRYPTOSDK_KMS_MRK_AWARE) ||
+        (test_type_idx == AWS_CRYPTOSDK_KMS_MRK_AWARE_DISCOVERY)) {
+        usleep(tenth_second_in_millis);
+    }
+}
+
 static int process_test_scenarios(
     struct aws_allocator *alloc,
     struct expected_outcome expected,
@@ -459,6 +468,7 @@ static int process_test_scenarios(
         bool not_supported;
         struct aws_cryptosdk_keyring *kr = keyring_for_master_key_spec(
             alloc, json_obj_mk_obj, keys_obj, test_type_idx, not_supported, client_supplier);
+        kms_delay(test_type_idx);
         if (!kr) {
             if (expected.success) {
                 if (not_supported) {