diff --git a/build-constraints.yaml b/build-constraints.yaml
index 1d0ca444..f5be7fb6 100644
--- a/build-constraints.yaml
+++ b/build-constraints.yaml
@@ -3815,6 +3815,7 @@ skipped-tests:
     - these
     - time-parsers
     - dlist-nonempty # QuickCheck2.11
+    - base64-bytestring-type # https://github.com/commercialhaskell/stackage/issues/3620#issuecomment-395947135
 
     # Uses Cabal's "library internal" stanza feature
     - s3-signer