English as a Medium of Instruction (EMI) might be very significant to help students to increase their ability in speaking. This research aims to investigate (1) the use of EMI at EED of UMY, (2) the speaking ability of EED students of UMY, and (3) the correlation between EMI at EED of UMY and the speaking skills of EED students of UMY. Quantitative method was used with the correlational research design. In this research, 108 questionnaires were distributed, and 93 were returned. The participants were EED students of UMY from batch 2016. SPSS 21 and Microsoft Excel were used to analyze the data. The findings showed that the use of EMI at EED of UMY is in high level (mean 3.3 of 4) which means that EMI was well implemented by EED lecturers of UMY in teaching-learning process. In addition, the speaking skills of EED students of UMY is in fair level (mean 6.5 of 9.5) which means that the speaking ability of EED students of UMY was not really good. The findings also revealed that there is positive and significant correlation between the use of EMI at EED of UMY and the speaking skills of EED students of UMY (p = 0.000, r = 0.753). Hence, H1 is accepted and it means that the higher the use of EMI at EED of UMY, the better the speaking skills of EED students of UMY will be.