The article deals with the study of dialect and colloquial elements in English fiction. The main aim of the study is to identify, analyze and characterize the significance of dialect and colloquial elements in modern fiction. The author studies the following terms “dialect”, “dialect words”, “colloquial words”. In the article dialect-colloquial elements are defined as speech units that characterize a certain dialect and are accompanied by some colloquial elements. The examples of dialect-colloquial elements are taken from the following works: “The Secret Garden” by Frances Hodgson Burnett (1911), “When Marnie Was There” by Joan G. Robinson (1967), “Harry Potter and the Prisoner of Azkaban” by J. K. Rowling (1999). The analysis of the works demonstrates that the functioning of dialect-colloquial elements is observed at different language levels: phonetic, grammatical and lexical. Reduction of sounds, devoicing or voicing of sounds, incorrect reading of the ending ‘ing’ are used at the phonetic level. The lexical level is characterized by the usage of obsolete forms of parts of speech and colloquial words. On the grammatical level a violation of the traditional grammar norms (no ending in the plural, the use of double negation, etc.) is found. The research proves that dialect-colloquial elements help to depict the characters vividly, convey the individuality of their speech, and sometimes serve as a means of satire.