While research highlights the benefits of participating in accelerator programs for early-stage startups, these programs may not provide uniform advantages to all founders. Given the important role of founders’ pre-entry knowledge and experience, we posit that the extent of performance benefits may vary based on the founding team’s background. Extant theories offer two countering mechanisms regarding whether pre-existing knowledge and experience provide advantages or disadvantages in gaining benefits from these programs. Analyzing data from 6,723 startups and their founding teams, we find that founders with greater pre-entry knowledge and experience derive greater benefits. Rather than leveling the playing field, accelerator participation may amplify performance differences between startups. These insights highlight the importance of founders’ pre-entry knowledge and experience when considering the benefits of startup accelerators.