Figurative language has received considerable attention from philosophers,cognitive psychologists and linguists due to the challenge it poses for theories of language comprehension.This thesis is an attempt to make a critique of irony theories,including the traditional views of irony,and several linguistic theories of irony especially the pragmatic ones,namely,Gricean irony theory,speech act analysis of irony and echoic-mention theory within a relevance-based framework.After pointing out the deficiencies and merits of these theories,I conclude that the echoic-mention theory uncovers the nature of irony and surpasses other related paradigm on this subject both in theory and in practice.