Across the education, public health, and human and social services areas, there is renewed interest in bringing agency representatives together to work on the promotion of student mental health and wellness. One of the aims of California's Prevention and Early Intervention (PEI) K-12 Student Mental Health (SMH) initiative funded under Proposition 63 is to build collaboration among K-12 school districts, counties, and regions to increase the effectiveness of SMH programs across the state. The Student Mental Health Policy Workgroup (SMHPW) was established to develop statewide policies that would impact K-12 programs, with a focus on enhancing linkages to services provided at schools or through the foster care system, county departments of mental health, special education programs, and community-based organizations. As part of its evaluation of activities funded under Proposition 63, SRI International and RAND researchers are evaluating the development, quality, and effectiveness of collaboration among K-12 SMH program partners. Through multiple methods, including document reviews, key informant interviews, and participant surveys, the SRI research staff is collecting data about the development, function, and goals of collaborative activities; the ongoing challenges and facilitators to successful collaboration; and the degree to which collaboration activities contributed to short- and long-term outcomes relevant to SMH PEI services and supports. Reported here are preliminary findings from 12 interviews conducted with these SMH key informants in the fall of 2013 separately for each K-12 CalMHFSA-funded program. Next steps are explored. [For related report, "California K-12 School and Community Collaborations: Facilitators, Challenges, and Impact on Student Mental Health," see ED561186.]