ABSTRACT  The purpose of this study was to investigate the effects of training foreign language teachers in the ACTFL-OPI-type training on student performance, instructional methods, and classroom materials in the secondary foreign language classroom. Proficiency-based instruction is one of ACTFL's most significant contributions to foreign language education; however, scarce research data are available on the effects of the ACTFL-OPI training at the secondary level. The hypothesis of this study was that teachers who had been trained in the ACTFL-OPI-type training would become more aware of factors contributing to a proficiency-oriented curriculum. It was carried out in the secondary schools in Pinellas County, Florida, in which teachers who were trained in the ACTFL-OPI-type training showed a 35 percent increase in personalized communication, more specifically when expressing feelings, opinions, and judgments in class. The analysis of variance (ANOVA) was found to be statistically significant in this communicative category (F= (1,4) = 13.07) at the .05 alpha level. Both quantitative and qualitative data were collected and analyzed. The results of the teacher interviews and questionnaires also supported the hypothesis that trained teachers were more aware of a proficiency-oriented curriculum. No significant differences were found on student performance. Further studies are suggested due to the large effect sizes found in the teacher categories