diff --git a/.circleci/config.yml b/.circleci/config.yml
index eef9d9011..b6724783d 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -73,7 +73,7 @@ jobs:
           working_directory: "/tmp"
           command: |
             env
-            /tmp/project/.circleci/setup-virtualenv.sh "${TAHOE_LAFS_TOX_ENVIRONMENT}" ${TAHOE_LAFS_TOX_ARGS}
+            /tmp/project/.circleci/setup-virtualenv.sh "${TAHOE_LAFS_TOX_ENVIRONMENT}" "${TAHOE_LAFS_TOX_ARGS}"
 
       - run: &RUN_TESTS
           name: "Run test suite"
@@ -82,7 +82,7 @@ jobs:
           working_directory: "/tmp"
           command: |
             env
-            /tmp/project/.circleci/run-tests.sh "${TAHOE_LAFS_TOX_ENVIRONMENT}" ${TAHOE_LAFS_TOX_ARGS}
+            /tmp/project/.circleci/run-tests.sh "${TAHOE_LAFS_TOX_ENVIRONMENT}" "${TAHOE_LAFS_TOX_ARGS}"
 
       - store_artifacts: &STORE_TEST_LOG
           # Despite passing --workdir /tmp to tox above, it still runs trial
@@ -235,13 +235,13 @@ jobs:
           <<: *SETUP_VIRTUALENV
           command: |
             env
-            sudo /tmp/project/.circleci/setup-virtualenv.sh "${TAHOE_LAFS_TOX_ENVIRONMENT}" ${TAHOE_LAFS_TOX_ARGS}
+            sudo /tmp/project/.circleci/setup-virtualenv.sh "${TAHOE_LAFS_TOX_ENVIRONMENT}" "${TAHOE_LAFS_TOX_ARGS}"
 
       - run:
           <<: *RUN_TESTS
           command: |
             env
-            sudo /tmp/project/.circleci/run-tests.sh "${TAHOE_LAFS_TOX_ENVIRONMENT}" ${TAHOE_LAFS_TOX_ARGS}
+            sudo /tmp/project/.circleci/run-tests.sh "${TAHOE_LAFS_TOX_ENVIRONMENT}" "${TAHOE_LAFS_TOX_ARGS}"
 
       - store_artifacts: *STORE_TEST_LOG
       - store_artifacts: *STORE_OTHER_ARTIFACTS