This study of 118 students who placed into basic skills sections of College English suggests that students’ self-beliefs may be a particularly important predictor of success in weak writers in first-semester courses. Two types of writing self-efficacy scales—a writing tasks/skills scale and an approach-to-writing scale—were developed to follow current composition practice more closely. Locus of control was the single most powerful predictor of success. This finding is congruent with theory about the importance of locus of control in new and ambiguous situations. High school performance, writing proficiency, and negative academic behaviors were also significant factors in regression analyses for both course grade and writing proficiency test. Various ways that writing instructors can help improve students’ self-beliefs are discussed.