Within foreign language classrooms, one intervention gaining recognition is LinguaFolio, a portfolio-based formative assessment designed to increase self-regulated learning. The question emerges whether such an intervention impacts student motivation, learning, and achievement. Researchers conducted a classroom-based, quasi-experimental, one-semester quantitative study with first-year French and Spanish classes at a Midwestern university. Students (N = 168) completed a pre- and post-questionnaire. Accuracy in self-assessment was investigated by comparing data from LinguaFolio to student performance on unit tests. The impact of instructor beliefs on LinguaFolio use was analyzed via questionnaires. The results indicate that LinguaFolio use is linked to increased student intrinsic motivation, increased task-value, and more accurate self-assessment of learning. This study supports LinguaFolio as an effective approach to increase self-regulated learning in students.