Academic achievement and the constructs that have been recently proposed as relevant to help students organize their study habits independently and effectively when taking online courses is important in the evaluation of the quality of student performance in higher education. Evaluating learner differences and how these differences affect students' academic performance is one way to understand the students' role in the online learning environment. The purpose of this study was to examine to what extent the constructs self-regulated learning, metacognition, and self-efficacy learning strategies, as measured by the scores on the Motivated Strategies for Learning Questionnaire (MSLQ), predict students' academic achievement in an online undergraduate psychology course. Academic achievement was measured using students' self-reported course grade. The participants consisted of 150 undergraduate students enrolled in a Research Methods Psychology course at a public, four-year higher education institution offering a fully online baccalaureate program in South Florida. The primary data collection method was the 81-item self-report questionnaire, Motivated Strategies for Learning Questionnaire (Pintrich, Smith, Garcia, & McKeachie, 1993), which has been widely used in educational research projects to assess college students' academic performance. The multiple regression analysis yielded an adjusted R2 = .12, p < .001 for the three predictors and academic achievement. The analysis of variance revealed F (4,145) = 5.199, p < .001, which is statistically significant. However, only self-regulated learning and self-efficacy were statistically significant predictors of students' academic achievement. These findings add support to the literature on the positive association found between these predictors and academic achievement for online learners. Educational implications and suggestions for further research are discussed.