<![CDATA[Vocabulary mastery is a fundamental component of English language learning because it supports students’ ability to understand and use the language. This study aimed to determine whether the use of flashcards had a significant effect on the vocabulary mastery of fifth-grade students at SDN 12 V Koto Kampung Dalam. The study employed a quantitative approach with a pre-experimental one-group pre-test and post-test design. The population and sample consisted of 13 fifth-grade students selected through total sampling. Data were collected using a 25-item vocabulary mastery test covering four aspects: word meaning, usage, form, and pronunciation. The data were analyzed using descriptive statistics, the Shapiro–Wilk normality test, and a Paired Sample t-test with SPSS version 20. The results showed that the students’ mean score increased from 34.52 in the pre-test to 80.19 in the post-test. The Shapiro–Wilk test showed significance values of 0.493 for the pre-test and 0.305 for the post-test, indicating that both datasets were normally distributed. The Paired Sample t-test produced a significance value of 0.000 (p < 0.05), with t = −13.569 and df = 12. These results indicate a statistically significant difference between students’ vocabulary mastery before and after the flashcard treatment. The findings suggest that flashcards can support vocabulary learning among fifth-grade students, particularly in word meaning, usage, form, and pronunciation.]]>
