This study analyses adult illiteracy in Lucknow, focusing on inequalities between different geographical regions, castes, age groups and genders. The reading ability of 1.06 million people in the 15–60 age group was tested, and the literacy rate found to be 65%—substantially lower than the census figures of 77% for Lucknow and 68% for Uttar Pradesh. Each socio-demographic dimension measured was a key determinant of literacy—disadvantaged groups had literacy rates substantially below the mean. Socio-demographic determinants also compound each other, highly disadvantaging some subgroups, an aspect that policymakers must take into consideration when developing policies to increase literacy equity.