diff --git a/.travis.yml b/.travis.yml
index 397de0a1..4f3d505c 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -7,12 +7,10 @@ matrix:
     - os: osx
       osx_image: xcode9.4
       env:
-        - GO111MODULE=on
         - MUTAGEN_TEST_END_TO_END=full
         - MUTAGEN_TEST_SSH=true
     - os: linux
       env:
-        - GO111MODULE=on
         - MUTAGEN_TEST_END_TO_END=full
         - MUTAGEN_TEST_SSH=true
         - MUTAGEN_TEST_DOCKER=true
diff --git a/appveyor.yml b/appveyor.yml
index df077cf7..788e6d8f 100644
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -10,7 +10,6 @@ clone_folder: C:\mutagen
 # Set Go versions and environment variables.
 environment:
   GOROOT: C:\go112
-  GO111MODULE: "on"
   MINGW_PATH: C:\mingw-w64\x86_64-7.2.0-posix-seh-rt_v5-rev1
   MUTAGEN_TEST_END_TO_END: "full"
   MUTAGEN_TEST_DOCKER: "true"