The aim of this study is to critically examine how heteronormativity and gender are constructed in English 5 textbooks; moreover, the study aims to investigate whether topics of heteronormativity and gender are further visible in textbooks published following the 2022 curriculum reform. This study is a textbook analysis using a thematic analysis method to establish patterns in six English 5 textbooks: three published before the reform and three published after the reform. The study draws on the theoretical framework of Biesta’s three domains of educational purpose, Moore’s taxonomy of heteronormativity, and Bem’s Gender Schema Theory. The results of the study conclude that most of the textbooks fall under the level of heteronormative erasure, meaning no representation of the non-heteronormative, while a few fall under heteronormative marginalization, meaning the non-heteronormative appears, but is stereotyped in the textbook. Moreover, traditional gender roles are present in the textbook, frequently portraying men as dominant leaders and women as nurturing and submissive.