A theory of the research training environment (RTE) proposed by Gelso (Counseling Psychologist, 8:7-35, 1979; Professional Psychology: Research and Practice, 24:468-476, 1993; The Counseling Psychologist, 25:307-320, 1997) is updated, and the research evidence that bears upon this theory is reviewed. Evidence accumulated over more than three decades supports the influence of the RTE on the research attitudes, research self-efficacy, and research productivity of graduate students in psychotherapy-related fields in psychology. Both the global RTE and 10 ingredients posited by RTE theory are reviewed. The ingredients that seem to have the greatest association with theorized training outcomes in students are (1) faculty modeling of scientific behavior, (2) positive reinforcement of students' scientific behavior, (3) teaching students, through the advising relationship and research teams, that science can be a partly social-interpersonal experience, and (4) teaching students that all research is flawed and limited. The training program faculty is responsible for arranging the training environment so that it will maximally impact psychotherapy graduate students' research attitudes, research self-efficacy, and productivity.