diff --git a/include/CLI/Validators.hpp b/include/CLI/Validators.hpp
index 03eb77b6..ba3cbe3c 100644
--- a/include/CLI/Validators.hpp
+++ b/include/CLI/Validators.hpp
@@ -32,6 +32,9 @@
 // Filesystem cannot be used if targeting macOS < 10.15
 #if defined __MAC_OS_X_VERSION_MIN_REQUIRED && __MAC_OS_X_VERSION_MIN_REQUIRED < 101500
 #define CLI11_HAS_FILESYSTEM 0
+#elif defined(__wasi__)
+// As of wasi-sdk-14, filesystem is not implemented
+#define CLI11_HAS_FILESYSTEM 0
 #else
 #include <filesystem>
 #if defined __cpp_lib_filesystem && __cpp_lib_filesystem >= 201703