Social cognitive theory (Bandura, 1986, 2001) and perceptual control theory (Powers, 1978, 1991) have described the self-efficacy/performance relationship in stark contrast. Additionally, recent work exploring these discrepancies has yielded future research suggestions yet to be undertaken (Bandura & Locke, 2003; Vancouver, Thompson, Tischner, & Putka, 2002; Yeo & Neal, 2006). Thus, this study explored the relationship between self-efficacy and performance between- and within-individuals over time. Division I collegiate American football players (N = 115) completed self-efficacy questionnaires and one-repetition maximum squat tests at 3 time points during off-season strength training. Results revealed that self-efficacy was positively related to squat performance at both the within- and between-person levels when controlling for athletes' raw past performance.