This research is an Experimental research design, the problem of the research is; Does the application of videos significantly affect on the students' pronunciation accuracy? And the objective of the study is to find out whether the application of videos significantly affect on the students' pronunciation accuracy. The sample of this research is the fifth semester students of English Study Program Faculty of Teacher's Training and Education The University of Sisingamangaraja XII Tapanuli (UNITA) in Academic Year 2018/2019. There were three phases in conducting the research; Pre-test phase, Treatment, and Post-test within in four weeks. The instrument used to collect the data was pronunciation accuracy with thirty questions or words to be pronounced. Based on the data gathered and its analysis, in which the mean score of pre-test is lower than the mean score of post-test or 10.23809524 < 20.76190476, in addition the t-test is higher than the table or 3.3755 > 1.684. In other words, the Null Hypothesis (Ho) is rejected and the Alternative Hypothesis (Ha) is accepted. As a conclusion, there is a significant effect of the application of videos on the students' pronunciation accuracy. Finally, based on the research conclusion, the researcher would like to recommend of using videos in dealing especially with English Phonology and Pronunciation.