This essay reconsiders the philosophical merits of Ayer’s verificationism. It concentrates on the first and second editions of Language, Truth and Logic (LTL), while also taking account of other writings by Ayer, as well as pertinent contributions to the continuing debate about verificationism. It starts out by identifying the importance of verificationism to Ayer’s attack on metaphysics, through elucidating its place in what I call his ‘anti-metaphysical argument’. Next it explains what verificationism is, emphasizing the difference between a semantic doctrine about the nature of meaning—‘the principle of verification’ (PV)—and an anti-metaphysical standard for meaningfulness—‘the criterion of verifiability’ (CV). It then concentrates on CV, considering the idea of ‘verifiability in principle’ and the distinction between strong and weak verifiability. With hindsight, CV fails to furnish the kind of knock-down argument against metaphysics Ayer sought. Nevertheless, it is a valuable dialectic tool for clarifying philosophical problems and theories and for challenging metaphysical pronouncements. But even in that dialectic capacity, CV presupposes that linguistic meaning is indeed linked to verification, that is, a variant of PV. I therefore engage in a brief semantic discussion of the role verification plays in meaning. At the end, I register a brief and ambivalent verdict on the legacy of Ayer’s verificationism.