This study examines gender representation in 10 current (2016-2020) US college-level general chemistry textbooks. On average, females were found to constitute 30% of images and 3% of the named science, technology, engineering, math, and medical (STEMM) professionals in the index. A male name appears on average every four pages of text, while a female name appears every 250 pages of text. Male overrepresentation is not driven by a pedagogical need to include specific individuals, since the textbooks only have eight names in common. Gender imbalance was ubiquitous among all publishers examined and observed in both traditional and electronic texts. We speculate that male overrepresentation in chemistry textbooks reflects and perpetuates unconscious gender bias in STEMM.