diff --git a/tools/docker/scripts/test_i-pi.sh b/tools/docker/scripts/test_i-pi.sh
index b87ecddb4b..1a1abf5ab6 100755
--- a/tools/docker/scripts/test_i-pi.sh
+++ b/tools/docker/scripts/test_i-pi.sh
@@ -33,6 +33,7 @@ set +e # disable error trapping for remainder of script
   cd run_1
   echo 42 > cp2k_exit_code
   sleep 2 # give i-pi some time to startup
+  export OMP_NUM_THREADS=2
   mpiexec -np 2 /workspace/cp2k/exe/local/cp2k.pdbg ../in.cp2k
   echo $? > cp2k_exit_code
 ) &