The effects of study abroad on students' language proficiency have been analyzed using a number of measures such as surveys, questionnaires and oral proficiency exams (Collentine, 2004; Freed, 1995; Segalowitz, & Freed, 2004). Furthermore, researchers have sought to determine the proficiency gains of study abroad (SA) students by comparing them to those who remained on campus or at-home (AH) (Félix-Brasdefer, 2004; Hernández, 2010; Isabelli-García, 2010). Although the Oral Proficiency Interview (OPI) and Simulated Oral Proficiency Interview (SOPI) have been used to measure the effects of study abroad (Davidson, 2007, 2010; Freed, So, & Lazar, 2003; Magnam, & Back, 2007), a review of the literature reveals that the Oral Proficiency Interview by Computer, the OPIc, has not been used to assess potential proficiency gains. Therefore, the purpose of this study was to measure oral proficiency gains among study-abroad (SA) and at-home (AH) students over the course of one semester, using the OPIc. This study presents a relevant contribution to the literature because (1) it builds upon previous empirical studies designed to assess the effects of a semester-long study abroad experience on students' language proficiency, in comparison to those who remained on campus; and (2) uses the OPIc as the measurement instrument. The two primary research questions are: (1) Is there a significant difference in the oral proficiency levels, as measured by the OPIc, between SA and AH students prior to a semester-long study abroad experience? and (2) Is there a significant difference in the oral proficiency levels, as measured by the OPIc, between SA and AH students after a semester-long study abroad experience?