diff --git a/.circleci/config.yml b/.circleci/config.yml
index 3c09aba92..488e42d44 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -7,6 +7,7 @@ jobs:
         environment:
           NOT_CRAN: true
           TRAVIS: false
+          OMP_NUM_THREADS: 1
           
     parallelism: 4
     steps: