This paper describes the development of a peer-focused capacity-building strategy that introduced key elements of CI and preliminary findings of Healthy Start grantees' progress with using CI as an approach to collaboration. Description The Collective Impact Peer Learning Networks (CI-PLNs) consisted of eight 90-min virtual monthly meetings and one face-to-face session that reviewed CI pre-conditions and conditions. Evaluation sources included: a facilitated group discussion at the final CI-PLN exploring grantee CI and CAN accomplishments (n = 57); routine evaluations (n = 144 pre, 46 interim, and 40 post PLN) examining changes in knowledge and practices regarding CI; and post CI-PLN implementation, three in-depth interviews with grantees who volunteered to discuss their experience with CI and participation in the CI-PLN. Assessment CI-PLN participants reported increased knowledge and confidence in the application of CI.