The past few decades have been marked by increasing awareness of issues pertaining to gender and sexuality, since both concepts have started being treated as continuums or spectrums, rather than as binaries. Therefore, the fields of gender and queer linguistics have been growing in significance, in an effort to identify underlying ideologies and biases in language, and to challenge them. Nevertheless, the reality is far from ideal, as gender inequalities and discrimination against non-normative sexualities are still prevalent in many sectors of life, one of which is education. In fact, education plays a prime role in shaping people’s views; not only do textbooks and other learning materials have a considerable effect on learners’ attitudes and sense of self, but also teachers’ beliefs and approaches can reinforce or challenge biases. In the present study, two English as a Foreign Language (EFL) textbooks used in Greek secondary public schools were examined, in order to investigate how gender and sexuality are represented on a lexical and discursive level. Additionally, three EFL teachers using said textbooks were interviewed to investigate their awareness of these topics as well as their attitudes and approaches towards them. The results from the textbook content analysis reveal that gender is overwhelmingly treated as a binary concept, and inclusivity is not always a consideration. Specifically, stereotypical gender representations were identified both on a word and a discourse level. Moreover, any topics explicitly concerning sexuality are avoided, and the only vocabulary made available for students to discuss these topics indexes heteronormativity. The teachers interviewed demonstrated some awareness of these issues, but were only able to point out very few problematic representations and examples of non-inclusive language. All teachers emphasised the need for training in order to be able to address these topics with their learners, and agreed that learners show limited awareness of discrimination and sexism in the language used in the textbooks. Furthermore, they argued that lack of progress in education is due to the fact that Greek society is not ready to embrace changes in how gender and sexuality are viewed. The conclusion drawn in the present study is that this lack of progress can potentially be attributed to how deeply rooted religious beliefs are in Greek society, reinforcing traditional gender roles and family values, while denouncing non-heterosexual expression. Overall, the present study corroborated the results found in other, similar investigations of EFL textbooks from around the world, and suggested that linguistic change cannot happen independently, but should be part of radical social reforms.