The main purpose of this paper is to highlight the importance of instrument makers during the early years of the nascent experimental psychology in order to assess their role in its development. We analysed and compared the reputations of German and French instrument makers who manufactured devices that populated experimental psychology laboratories in Europe, the United States and the rest of the world. In the first part of the article we present a list of the main firms mentioned by Münsterberg and Titchener that provided instruments for the equipment of psychology laboratories at the turn of the twentieth century. In the second part of the paper the renown of German, English, American, French, and other instrument makers is investigated via the prizes awarded at some international exhibitions. Although the Zimmermann firm was well known in the domain of psychology because of its close relation with Wundt’s laboratory, several other firms also had an international reputation in psychology, notably the French firm Verdin. The last part of the paper is a comparative analysis of the international importance of the Zimmermann and Verdin firms based on the purchase of instruments by two famous directors (Münsterberg and Titchener) of American psychology laboratories around 1900.