Limited knowledge of vocabulary was the main problem in learning the language. It means that it was caused by a big problem if someone did not have a rich vocabulary. The large the vocabulary students master, the better they perform
their language. This study aims to determine students' difficulties in learning vocabulary mastery for students of the English Education Study Program of IKIP PGRI Pontianak in the 2021/2022 academic year. This research is a descriptive survey research with a quantitative descriptive method. The participants in this study were 30 fourth semester students. Data using indirect communication techniques with online questionnaires (close-ended) as a tool. The findings stated that all students had difficulty in learning vocabulary mastery. The results showed that all aspects of difficulty in mastering vocabulary were on average in agreeing on skills, with difficulty in learning vocabulary mastery in the first rank using grammar, the second in spelling, the third in pronouncing, and finally understanding the meaning and what factors made it difficult for students. in learning vocabulary, namely internal factors and external factors. From the discussion, it can be concluded that difficulties in vocabulary mastery, pronunciation, spelling, grammar, and meaning, are the indicator of students’ difficulties in vocabulary mastery, and results showed that grammar is the dominant aspect it is important to know student’s difficulties in mastering
vocabulary.

Keywords: student difficulties, vocabulary mastery