Purpose: School health centers (SHC) that provide comprehensive health care may improve access and quality of care for students; however, published impact data are limited. Methods: We evaluated access and quality of health services at an urban high school with a SHC compared with a school without a SHC, using a quasiexperimental research design. Data were collected at the beginning of the school year, using a paper and pencil classroom questionnaire (n = 2,076 students). We measured SHC impact in several ways including grade by school interaction terms. Results: Students at the SHC school were more likely to report having a regular healthcare provider, awareness of confidential services, support for health services in their school, and willingness to utilize those services. Students in the SHC school reported higher quality of care as measured by: respect for their health concerns, adequate time with the healthcare provider, understandable provider communications, and greater provider discussion at their last visit on topics such as sexual activity, birth control, emotions, future plans, diet, and exercise. Users of the SHC were also more likely to report higher quality of care, compared with either nonusers or students in the comparison school. Conclusions: Access to comprehensive health services via a SHC led to improved access to health care and improved quality of care. Impact was measureable on a school-wide basis but was greater among SHC users. (C) 2013 Society for Adolescent Health and Medicine. All rights reserved.