Vocabulary acquisition is significant for language learning. Vocabulary acquisition itself entails tremendous amounts of the language exposure. Students could utilize applications to assist their vocabulary growth. One of the applications that has been proven by studies for carrying positive impacts in vocabulary learning and acquisition is YouTube.  However, there is not yet any statistical proof that shows if there is any correlation between  the intensity of the language exposure from YouTube and the vocabulary acquisition. Therefore, This research aimed to investigate the correlation between the intensity of YouTube usage and vocabulary acquisition. This research used correlational research. The participants of this research were 65 CLS II students from English Language Education Study Program of Sanata Dharma University. A 2 Weeks Journal and a B2 CEFR Vocabulary Test were used as the instruments of this research.  The participants were asked to fill the journal for 14 days to record their intensity of watching English YouTube videos. Then, the students were tested using  B2 CEFR Vocabulary Test on the last day of the journal filling or after they had done it to measure their vocabulary acquisition. The data gathered then tested using Pearson’s Product Moment Simple Correlation formula.