This research was conducted with the aim of finding out whether the use of word square media is effective or not in teaching vocabulary and how significant it is for students at SMP 1 Sungai Kunyit in academic 2023. This research was designed in the form of pre-experimental research, in the form of a one group pre-test post-test design. The population of this study was eighth grade students. The sample was class VIII-B, totaling 26 students. Samples were taken using random sampling. Measurement techniques are used to collect data. The data collection tool is a multiple choice test. Data were analyzed using descriptive statistics. Research findings show Word Square is effective in teaching vocabulary mastery. This shows that the average score increased in the pre-test and post-test (56.77 to 76.23). This shows that the use of word square media is applied in teaching vocabulary. Finally, it is proven by the paired sample t test value, the sig value is smaller than ɑ (0.00<0.05) which means Ha is accepted. The effect of
using Word Square is a medium effect level based on the Cohen effect. The value is 0.57, which means a moderate influence on increasing students' vocabulary mastery.
The results of this research are that the use of word squares can be applied as a learning medium for further learning. Word square is an effective medium for improving vocabulary mastery for young learners.

Keywords: Word Square, Vocabulary Mastery, Pre-Experimental Research