Assessing student learning is a key component to education. Most institutions assess learning using a score-based grading system. Such systems use multiple individual assignment scores to produce a cumulative final course grade, which may or may not represent what a student has learned. Standards-based grading offers an alternative that addresses the need to directly assess how well students are developing toward meeting the course objectives. The course objectives are the focal point of the grading system, allowing the instructor to assess students on clearly defined objectives throughout the course. The system assesses how well students become proficient in the course objectives over the duration of the course. This study extends the use of standards-based grading at the K-12 level into the realm of undergraduate science, technology, engineering, and mathematics (STEM) education. Five STEM courses pilot tested the integration of a standards-based grading system to investigate how it impacts affective and cognitive student behaviors. The results suggest that a standards-based grading system increased student domain-specific self-efficacy, was perceived as valuable, and helped students develop more sophisticated beliefs about STEM knowledge.