Gender bias in textbooks (GBIT) is a low-profile education issue, given the 72,000,000 children who still have no access to schooling, but this article argues that GBIT is: (1) an important, (2) near-universal, (3) remarkably uniform, (4) quite persistent but (5) virtually invisible obstacle on the road to gender equality in education--an obstacle camouflaged by taken-for-granted stereotypes about gender roles. Specifically, GBIT: (1) is important because (a) textbooks occupy approximately 80% of classroom time, and (b) it may contribute to lowering girls' achievements, especially in weak schools in poor countries; (2) has been found worldwide to varying degrees (except, perhaps, Sweden in recent years); (3) involves nearly identical patterns of under-representation of females, plus stereotypes of both genders' occupational and household roles that overwhelmingly underplay women's rising worldly importance; (4) is decreasing very slowly, according to "second generation" re-studies; and (5) remains obscured by the "hidden-in-plain-sight" system of gender stratification and roles. Case studies from Syria, India, Romania, China and the US document these points. Other case studies from Sweden and Latin America describe government initiatives to reduce GBIT, with differing levels of success. Totally revising textbooks (and curricula) to eliminate this bias is quite unlikely, partly because it is very costly. The article concludes by presenting inexpensive alternate methods that "can" combat GBIT.