Sarcasm is commonly defined as “the use of remarks that clearly mean the opposite of what they say, made in order to hurt someone's feelings or to criticize something in a humorous way” (online Cambridge Dictionary, 2019). As such it is often defined as hostile humor and mainly referred to in a negative context. The aim of this thesis is to show that sarcasm is widely used today for other purposes other than strictly as a mechanism to criticize something or somebody. To support the objective of this thesis, examples from the first two seasons of the sitcom The Big Bang Theory have been selected for analysis. Considering that in order to understand sarcasm one has to think beyond the literal meaning of an utterance, sarcasm is often left undetected, which is why the importance of the implicit part of an utterance is discussed in this paper. In fact, there are number of factors that are crucial for sarcasm detection, such as mutual background knowledge between the speaker and the hearer, difficulties comprehending other people’s intentions, emotions or attitudes, understanding non-linguistic signs such as intonation and facial expressions, and the context – which is regarded as a psychological construct in the form of hearer’s assumptions from the perspective of Relevance Theory. Sperber and Wilson’s Relevance Theory (1986) represents one of the groundbreaking works in pragmatics because it introduced cognitive linguistics into pragmatics and, among other things, in terms of humor it recognized the communicative intention of humor and the importance of the relationship between the individual and the context.