We describe the impact of school health centers in Alameda County, California, on adolescents' access to care and their mental and physical health outcomes. We used a multimethod evaluation of 12 school health centers to track data on clients (n=7410), services, and provider-reported outcomes; client pre-post surveys (n=286); and student focus groups (n=105 participants). School health centers were the most commonly reported source of medical (30%), family planning (63%), and counseling (31%) services for clients. Mental health providers reported significant improvements (P<.05) from baseline to follow-up in clients' presenting concerns and resiliency factors. Medical providers and clients also reported general improvements in reproductive health, particularly in the use of birth control other than condoms. Student focus group participants noted that school health centers helped improve access to services students might not seek out otherwise, particularly counseling and family planning services. Furthermore, students noted that they liked school health centers because of their confidentiality, free services, convenience, and youth-friendly staff. School health centers increase access to care and improve mental health, resiliency, and contraceptive use.