diff --git a/Makefile b/Makefile
index a24a5276..4232588e 100644
--- a/Makefile
+++ b/Makefile
@@ -5,6 +5,8 @@
 export GO111MODULE = on
 # opt-in to vendor deps across all go commands.
 export GOFLAGS = -mod=vendor
+# enable consistent Go 1.12/1.13 GOPROXY behavior.
+export GOPROXY = https://proxy.golang.org
 
 # Build