This quantitative investigation examined the influence of low and high self-efficacy on candidate teacher academic performance in a foreign language teaching methodology course through testing the speculation that high self-efficacy levels would improve pedagogical-content knowledge (PCK). Positivism guided the research design at the levels of ontology (a single conceptualization of self-efficacy) and epistemology (detachment from rather than interactions with the subjects). The positivist paradigm also guided this study at the methodology level through using a nomothetic research strategy (causal comparative), data collection methods (self-efficacy questionnaire and PCK achievement test), data analysis techniques (independent-groups t-test and its non-parametric counterpart Mann-Whitney U test). Data analysis indicated no significant differences between low and high self-efficacious students in their PCK. The study raised questions about examining self-efficacy through self-reporting measures and cast serious doubts on the positive influence of high self-efficacy on academic achievement. (Contains 9 tables and 1 figure.)