diff --git a/build-constraints.yaml b/build-constraints.yaml
index d3b3af53..e6d35224 100644
--- a/build-constraints.yaml
+++ b/build-constraints.yaml
@@ -7273,6 +7273,7 @@ expected-test-failures:
     - simple-affine-space
     - xml-picklers # https://github.com/Philonous/xml-picklers/issues/5
     - freckle-app # https://github.com/commercialhaskell/stackage/issues/6197
+    - markdown # https://github.com/snoyberg/markdown/issues/39
 
     # Assertion failures due to module name ambiguity
     # (These _should_ be fixed by using the `hide` section of this file)