diff --git a/modules/ECMQueryQmake.cmake b/modules/ECMQueryQmake.cmake
index 8f4cf17..0a3129d 100644
--- a/modules/ECMQueryQmake.cmake
+++ b/modules/ECMQueryQmake.cmake
@@ -1,25 +1,30 @@
 find_package(Qt5Core QUIET)
 
 set(_qmake_executable_default "qmake-qt5")
 if (TARGET Qt5::qmake)
     get_target_property(_qmake_executable_default Qt5::qmake LOCATION)
 endif()
 set(QMAKE_EXECUTABLE ${_qmake_executable_default}
     CACHE FILEPATH "Location of the Qt5 qmake executable")
 
 # This is not public API (yet)!
 function(query_qmake result_variable qt_variable)
+    if(NOT QMAKE_EXECUTABLE)
+        set(${result_variable} "" PARENT_SCOPE)
+        message(WARNING "Should specify a qmake Qt5 binary. Can't check ${qt_variable}")
+        return()
+    endif()
     execute_process(
         COMMAND ${QMAKE_EXECUTABLE} -query "${qt_variable}"
         RESULT_VARIABLE return_code
         OUTPUT_VARIABLE output
     )
     if(return_code EQUAL 0)
         string(STRIP "${output}" output)
         file(TO_CMAKE_PATH "${output}" output_path)
         set(${result_variable} "${output_path}" PARENT_SCOPE)
     else()
         message(WARNING "Failed call: ${QMAKE_EXECUTABLE} -query \"${qt_variable}\"")
         message(FATAL_ERROR "QMake call failed: ${return_code}")
     endif()
 endfunction()