This study investigates the impact of constructivist teaching methods on achievement and misconceptions in mechanics, with a focus on gender differences. The research involved 88 first-year physics students enrolled in the physics teacher training program. Using a quasi-experimental design, students were divided into experimental (constructivist teaching) and control (traditional teaching) groups, with each group completing a pre- and post-test to assess changes in understanding and misconceptions around key mechanics concepts, particularly the concept of force. Results reveal that the constructivist intervention significantly improved achievement scores, especially for female students, thus reducing the gender gap in physics achievement. However, persistent misconceptions were observed in specific, abstract topics, such as motion in frictionless environments and rocket propulsion, which were less effectively addressed by the constructivist approach alone. These findings contribute to the literature on gender-sensitive instructional strategies and points out that constructivist approaches can be further optimized to support conceptual understanding in complex scientific domains.