diff --git a/modules/ECMAddAppIcon.cmake b/modules/ECMAddAppIcon.cmake
--- a/modules/ECMAddAppIcon.cmake
+++ b/modules/ECMAddAppIcon.cmake
@@ -162,7 +162,7 @@
                   ${sidebar_icons_at_128px}
                   ${sidebar_icons_at_256px})
 
-    if (NOT (mac_icons OR mac_sidebar_icons))
+    if (APPLE AND NOT (mac_icons OR mac_sidebar_icons))
         message(AUTHOR_WARNING "No icons suitable for use on macOS provided")
     endif()
 
@@ -178,7 +178,7 @@
                               ${icons_at_512px}
                               ${icons_at_1024px})
 
-    if (NOT (windows_icons_modern OR windows_icons_classic))
+    if (WIN32 AND NOT (windows_icons_modern OR windows_icons_classic))
         message(AUTHOR_WARNING "No icons suitable for use on Windows provided")
     endif()