This paper examines a Cameroonian ESL textbook – Mastering English: Student’s Book for Form 1, with the aim of investigating gender representation in this textbook. The study employed a document analysis design because data for the study was collected exclusively from the textbook. Data was collected by observing the images and by reading through the passages, dialogues and sentences in the textbook, and noting the various representations of the male and female genders. The study adopted the Critical Discourse Analysis approach to analyse data related to visibility, occupational roles and firstness in presentation in order to unveil the inequalities and power imbalance between the representation of the male and female genders in the textbook. The findings revealed that the male gender is given more visibility above the female in terms of pictorial and lexical representations. Besides, more occupational roles are assigned to males than to females in the textbook. Males equally dominate the first position in dialogues, common noun, proper noun and pronoun pairs. The study concludes that the dominance of the male over the female gender observed in the textbook is a replication of the gender imbalance that exists in the Cameroonian society. This study therefore brings to the limelight these gender imbalances in Cameroonian textbooks, and recommends that curriculum developers should always endeavour to strike a balance between the representation of the male and the female genders when designing educational materials.