diff --git a/native/libcst/Cargo.toml b/native/libcst/Cargo.toml
index 6ee3bccfd..b52b90151 100644
--- a/native/libcst/Cargo.toml
+++ b/native/libcst/Cargo.toml
@@ -36,7 +36,7 @@ trace = ["peg/trace"]
 
 [dependencies]
 paste = "1.0.9"
-pyo3 = { version = ">=0.17", optional = true }
+pyo3 = { version = ">=0.17,<0.20", optional = true }
 thiserror = "1.0.37"
 peg = "0.8.1"
 chic = "1.2.2"