Any modern, moderately intellectually mature (MMIM) believer in God faces a variety of epistemic defeaters of their belief in God. Epistemic defeaters challenge the rationality of a belief. After explaining the notion of a defeater and discussing various ways and targets of defeat, this Element categorizes the many defeaters of belief in God into four classes: rebutting, undercutting, base defeaters, and competence defeaters. Then, several general defeaters of theistic belief are examined in some detail: the superfluity argument, the problem of unpossessed evidence, various forms of debunking arguments, and a cumulative case competence defeater. The typical MMIM believer, it is argued, has resources to resist these defeaters, although the cumulative case competence defeater has some force. The strength of its force depends on the strength of grounds for theistic belief and of various defeaters and deflectors for the competence defeater. No easy general defeater of theistic belief is found.