|| A project was designed to find out if standards-based self-assessment, applied to laboratory reports, enhanced learning for first and second year biology students. Student participation, report grades and student feedback were analysed to measure the effectiveness of a self-assessment process. As the term progressed, almost all (>90%) first year students with A or B+ grades (>70% mark) used self-assessment. Over time first year student participation in self-assessment increased and their ability to accurately self-assess improved. Self-assessors achieved a higher average laboratory report mark compared to non-participants. The study concluded that the introduction of self-assessment had a positive impact on first year engagement and performance. The findings were less clear for the second year cohort. Evidence that students with low-grades did not know how to improve their work showed that the self-assessment intervention alone was insufficient to enhance learning for this group. Student surveys indicated a positive reaction from both cohorts of students to the standards-based self-assessment pro-forma. Recommendations are made for the application of self-assessment in laboratory report writing for junior undergraduates. Self-assessment training and improved feedback methodologies are proposed to deepen the efficacy of self-assessment as a tool to enhance learning in the laboratory.