Science, technology, engineering, and mathematics (STEM) programs at top colleges and universities in the United States have increasingly promoted peer collaboration as a highly effective educational approach to learning in the twenty-first century. But what are students’ actual collaborative experiences in these programs, and are they equitable? To answer these questions, I draw on a qualitative case study of an elite engineering school involving in-depth interviews with engineering undergraduates and administrators, as well as ethnographic observations of life at the school over the course of two and a half years. I argue that the culture and structure of elite STEM programs actually undermine the equitable promises of collaborative learning by creating more positive collaborative experiences for privileged students than for their less-privileged counterparts, which positions privileged students to receive more academic help, support, and learning opportunities. I find that although students are influenced, expected, and instructed to collaborate, the inexplicit rules and limited structuring around how and with whom to do so lead students to rely on their own backgrounds to navigate the collaborative scene. This context enables privileged students—namely those from class-advantaged high school contexts as well as male and White and Asian students (or those with intersectional privileges)—to experience the most success with collaboration. The findings suggest that STEM programs’ promotion of collaborative learning approaches falls short in engineering equitable educational advantages for students of all backgrounds.