Embodiments of the present invention provide a method, system and computer program product for translation verification of source strings for controls in a target application graphical user interface (GUI). In an embodiment of the invention, a method for translation verification of source strings for controls in a target application GUI can include loading a target GUI for an application under test in a functional testing tool executing in memory by a processor of a computing system, retrieving different translated source strings in a target spoken language for respectively different control elements of the target GUI and, determining a score for each one of the translated source strings. Thereafter, an alert can be provided in the functional testing tool for each translated source string corresponding to a determined score failing to meet a threshold value, such as a score that falls below a threshold value, or a score that exceeds a threshold value.