Grant writing is an essential skill to develop for academic and other career success but providing individual feedback to large numbers of trainees is challenging. In 2014, we launched the Stanford Biosciences Grant Writing Academy to support graduate students and postdocs in writing research proposals. Its core program is a multi-week Proposal Bootcamp designed to increase the feedback writers receive as they develop and refine their proposals. The Proposal Bootcamp consisted of two-hour weekly meetings that included mini lectures and peer review. Bootcamp participants also attended faculty review workshops to obtain faculty feedback. Postdoctoral trainees were trained and hired as course teaching assistants and facilitated weekly meetings and review workshops. Over the last six years, the annual Bootcamp has provided 525 doctoral students and postdocs with multi-level feedback (peer and faculty). Proposals from Bootcamp participants were almost twice as likely to be funded than proposals from non-Bootcamp trainees. Overall, this structured program provided opportunities for feedback from multiple peer and faculty reviewers, increased the participants' confidence in developing and submitting research proposals, while accommodating a large number of participants.