Reflective writing may be undervalued as purely expressive rather than a critical or an academic tool in undergraduate public health biology courses. When grounded in course concepts and academic learning, a reflective essay can be a learning tool for students that helps them use discipline knowledge and apply it to real-world issues. Studies on teaching reflection have identified its value for training students in critical thinking and improving self-regulated learning. Considering Gibbs’ Reflective Cycle framework, in this article, we detail the design, implementation, and evaluation of a reflective writing assignment integrated into a lower-year undergraduate public health biology course. Through the design and implementation of the reflective writing assignment, four key lessons are drawn. First, reflective writing assignments facilitate learning and course enjoyment. Second, writing workshops improve the quality of reflective writing assignments.