diff --git a/Dockerfile b/Dockerfile
index cb20b2746..18850f0cc 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -79,6 +79,10 @@ ADD .git/HEAD GIT_HEAD
 # Add all of the files!
 ADD . .
 
+# If a pip package is licensed as GPL, fail the build.
+# If this fails the build, change the last grep to be "grep -B 10 GPL" to see what package is GPLed.
+RUN test -z "$(cat requirements.txt | grep -v "^-e" | awk -F'==' '{print $1}' | xargs pip show --disable-pip-version-check | grep -v LGPL | grep GPL)"
+
 # Run the tests
 ARG RUN_TESTS=true
 ENV RUN_TESTS ${RUN_TESTS}