Black and Brown men continue to be underrepresented in engineering. One explanation for the dearth of Black and Latino men in engineering is that engineering (and STEM) identity often is not inclusive of People of Color. As a result, Black and Brown boys may be less likely to become interested in STEM subjects. The purpose of this study, then, was to investigate how the components of one afterschool engineering program tap into engineering identity formation among fourth- and fifth-grade Black and Brown boys. Leveraging research on the STEM and engineering identity, we argue that the program and its key components play both constructive and protective roles. This study comprises a case study of an afterschool engineering program completing its third year of implementation at three elementary schools. Over four semesters, we recruited approximately 60 students from the three schools and 21 mentors to participate in the study. We collected data via one-on-one interviews, focus groups, and observations. We found that engineering design activities are constructive, offering the young Black and Brown boys opportunities to engage with the work of engineers. The mentors played constructive roles by recognizing the students' engineering work. The mentors also played a protective role, buffering against identity interference and cultivating a sense of belonging. We conclude by discussing how the findings contribute to existing research on engineering identity and making recommendations for practice.