Starting with initiatives dating back to the mid-1800s, we provide a high-level review of the key trends and developments in the application of applied psychology to the field of occupational safety. Factory laws, basic worker compensation, and research on accident proneness comprised much of the early work. Thus, early research and practice very much focused on the individual worker, the design of their work, and their basic protection. Gradually and over time, the focus began to navigate further into the organizational context. One of the early efforts to broaden beyond the individual worker was a significant focus on safety-related training during the middle of the 20th century. Toward the latter years of the 20th century and continuing the move from the individual worker to the broader organizational context, there was a significant increase in leadership and organizational climate (safety climate) research. Ultimately, this resulted in the development of a multilevel model of safety culture/climate. After discussing these trends, we identify key conclusions and opportunities for future research.