As an innovative pedagogy, flipped classroom approach enables instructors to move direct instruction out of class and convert class time to a dynamic learning environment where students engage in teamwork, problem‐solving, and other interactive activities. Previous research has concluded that, when implemented well, flipped learning has the potential not only to increase learning gain but also to improve students’ professional skills such as teamwork, communication, and life‐long learning, which are deemed to be critical in engineering education and practice. This study aimed to examine the development of teamwork skills in a flipped civil engineering course. A sequential mixed‐method approach was adopted to understand students’ attitude toward teamwork, confidence in teamwork, and teamwork skill development. Quantitative data included pre‐ and postcourse surveys and peer evaluation (PE) and self‐evaluation (SE) while qualitative data included focus group interviews. Results indicated that students’ attitudes toward teamwork slightly improved, but it was not statistically significant. Confidence in teamwork, however, significantly improved after being engaged in a semester‐long team project. Teamwork skill development was assessed through four PE and SE conducted after each major project milestone. Findings are discussed and implications for classroom implementations and future research are presented.