Gender becomes one of the essential factors that are always considered in the various relationships among variables in the educational field. The purpose of this study is to examine the involvement of gender differences in the enhancement of college students' English achievement using inquiry-based learning. A quasi-experimental two-way factorial design among groups was applied to carry out this study. 300 Indonesian EFL (English for Foreign Language) college students were randomly allocated to one of two groups. The experimental group (N = 150) consisted of 85 females and 65 males who were given inquiry-based learning. Meanwhile, the control group (N = 150) contained 75 males and 75 females who were given direct learning. An achievement English test containing 50 multiple choice problems was administered to them before and after their involvement. The data was analyzed using some tests such as the independent sample t-test, paired sample t-test and factorial between two groups ANCOVA (Analysis of Covariance) and SPSS v.29 was used to promote these analyses. The results of this recent study showed that the intervention of inquiry-based learning has a significant and positive effect on enhancing college students' EFL achievement. Moreover, there is significant evidence that gender differences are involved in the enhancement of college students' English achievement in inquiry-based learning. There is a statistically significant relationship between gender and inquiry-based learning. This study implies that inquiry-based learning can be applied to enhance students' achievement in Indonesian EFL colleges.