ABSTRACT As foreign language education moves toward proficiency‐based teaching and testing, few studies have looked systematically at its effects on student performance, classroom methods and materials, teacher expectations, and program administration, particularly at the secondary level.The study reported here examines the effects of district‐wide ACTFL Oral Proficiency Interview (OPI) testing. Specifically, the study asks, “Do students who perform well on the OPI also perform well on more traditional measures of student success?” and “What other effects, if any, does oral proficiency testing have on a foreign language program?” Multivariate analyses of variance were performed on scores from the OPI and the subscales of the College Board Foreign Language Achievement Test from 492 third, fourth, and fifth year high school foreign language students. Qualitative data include information from interviews, observations, and a questionnaire distributed to administrators, teachers and students. Significant correlations were found between student performance at the higher levels of the OPI and on the achievement tests. Furthermore, the benefits of the oral proficiency testing program extended beyond student performance to the sense of common direction it provided to teachers and programs.