diff --git a/libaegisub/include/libaegisub/option_value.h b/libaegisub/include/libaegisub/option_value.h
index 6cf960597..cc2aaaf10 100644
--- a/libaegisub/include/libaegisub/option_value.h
+++ b/libaegisub/include/libaegisub/option_value.h
@@ -23,6 +23,9 @@
 #include <libaegisub/exception.h>
 #include <libaegisub/signal.h>
 
+// X11 is awesome and defines Bool to int
+#undef Bool
+
 namespace agi {
 DEFINE_BASE_EXCEPTION_NOINNER(OptionValueError, Exception)
 DEFINE_SIMPLE_EXCEPTION_NOINNER(OptionValueErrorInvalidType, OptionValueError, "options/invalid_type")
diff --git a/src/preferences_base.cpp b/src/preferences_base.cpp
index ff8b75d1b..f088f9c25 100644
--- a/src/preferences_base.cpp
+++ b/src/preferences_base.cpp
@@ -42,6 +42,8 @@
 #include <wx/stattext.h>
 #include <wx/treebook.h>
 
+#undef Bool
+
 #define OPTION_UPDATER(type, evttype, opt, body)                            \
 	class type {                                                            \
 		std::string name;                                                   \