diff --git a/cmake/nanobind-config.cmake b/cmake/nanobind-config.cmake
index 312e828f..82d8abec 100644
--- a/cmake/nanobind-config.cmake
+++ b/cmake/nanobind-config.cmake
@@ -28,7 +28,7 @@ endif()
 
 # PyPy sets an invalid SOABI (platform missing), causing older FindPythons to
 # report an incorrect value. Only use it if it looks correct (X-X-X form).
-if(DEFINED NB_SOABI AND "${NB_SOABI}" MATCHES ".+-.+-.+")
+if(DEFINED NB_SOABI AND "${NB_SOABI}" MATCHES ".+-.+_.+")
   set(NB_SUFFIX ".${NB_SOABI}${NB_SUFFIX_EXT}")
 endif()