The current reform movement in science education promotes standards‐based teaching, including the use of inquiry, problem solving, and open‐ended questioning, to improve student achievement. This study examines the influence of standards‐based teaching practices on the achievement of urban, African‐American, middle school science students. Science classes of teachers who had participated in the professional development (n = 8) of Ohio's statewide systemic initiative (SSI) were matched with classes of teachers (n = 10) who had not participated. Data were gathered using group‐administered questionnaires and achievement tests that were specifically designed for Ohio's SSI. Analyses indicate that teachers who frequently used standards‐based teaching practices positively influenced urban, African‐American students' science achievement and attitudes, especially for boys. Additionally, teachers' involvement in the SSI's professional development was positively related to the reported use of standards‐based teaching practices in the classroom. The findings support the efficacy of high‐quality professional development to change teaching practices and to enhance student learning. © 2000 John Wiley & Sons, Inc. J Res Sci Teach 37: 1019–1041, 2000