This paper provides a critique of existing research on the internationalization process of the firm and proposes an agenda for future inquiry. In recent years, process approaches have received increasing attention in management research, leading to a more refined understanding of the distinction between process and variance paradigms. We apply a process lens to a well‐established sub‐field of international business, namely the internationalization process of the firm. We review how this research tradition has evolved over four decades. The review commences with a reassessment of the seminal ‘stage models’ that date back to the 1970s. It then proceeds to classify subsequent research on the basis of whether it includes process data and/or process theorizing. It is found that the majority of studies in this review do not combine process data with process theorizing. We show how, even in studies that contain some process elements, a process approach is not always sustained throughout the paper. On the basis of this review, six research themes are proposed, which would form the basis for a process agenda for future research.