© the several contributors 2017. Explanationism is an attractive family of theories of epistemic justification. In broad terms, explanationism is the idea that what a person is justified in believing depends on their explanatory position. At its core, explanationism involves commitment to the claim that the fact p would best explain a body of evidence if p were true is itself evidence that p is true. In slogan form: explanatoriness is evidentially relevant. Despite its plausibility, explanationism has been criticized for various reasons. This chapter strengthens the case for explanationism by defending it from a recent attack by Elliott Sober and William Roche.