Women’s education is among the significant factors contributing to the reduction in fertility rates in developing countries. India has experienced a rapid decline in total fertility rates and significant improvements in women’s educational attainment over the past several decades. However, little is known about the cohort-specific implications of educational expansion on fertility decline in India. Thus, this study aimed to elucidate the pattern of fertility differentials based on education level and assess the contribution of changes in women’s educational attainment to the fertility decline across different cohorts in India. Education-based differences in cohort fertility rates (CFRs) were analysed among the birth cohorts of 1945–1949 to 1975–1979, utilising data from five rounds of the Indian National Family Health Survey conducted between 1992–1993 and 2019–2021. Demographic decomposition methods were employed to examine the contribution of changes in women’s educational composition to fertility decline. The results suggest that the differences in fertility based on educational attainment have gradually declined over birth cohorts. The decomposition results show that the composition changes in women’s education contributed to approximately one-fifth of the decline in CFRs in India. However, within urban and rural areas of Indian macro-regions, the composition changes in women’s education were minimal. Uneducated women were the primary driver of CFR decline across social groups and macro-regions. Thus, the role of education in fertility decline lies more in the diffusion of reproductive behaviours, which has contributed to reducing fertility differentials across social strata.