diff --git a/tests/jobs/nosim/test_nosim.py b/tests/jobs/nosim/test_nosim.py
index 395214e8d..b9d43b506 100644
--- a/tests/jobs/nosim/test_nosim.py
+++ b/tests/jobs/nosim/test_nosim.py
@@ -1,3 +1,4 @@
+import sys
 import os
 import shutil
 import subprocess
@@ -8,6 +9,13 @@
 import ert_shared.hook_implementations
 
 
+@pytest.mark.skipif(
+    sys.platform == "darwin", reason="Skip test for Mac OS - invalid use of sed"
+)
+# The GNU extension for the sed command on osx behaves slightly different.
+# The result when running the forward model job is as follow:
+# cat insert_nosim.stderr.1
+# sed: 1: "TEST.DATA": invalid command code T
 @pytest.mark.parametrize(
     "nosim_command,data_input,data_expected",
     [