diff --git a/build-constraints.yaml b/build-constraints.yaml
index e31076fb..bd2a2f2b 100644
--- a/build-constraints.yaml
+++ b/build-constraints.yaml
@@ -4890,6 +4890,11 @@ packages:
       # https://github.com/commercialhaskell/stackage/issues/4964
       - prettyprinter < 1.5
 
+      # https://github.com/commercialhaskell/stackage/issues/4966
+      - megaparsec < 8
+      - megaparsec-tests < 8
+      - hspec-megaparsec < 2.1
+
 # end of packages
 
 # Package flags are applied to individual packages, and override the values of