The subject of this work is a comprehensive contrastive analysis of two Bosnian dialects: 1) the Ekavian-jekavian dialect of Tešanj and Maglaj and 2) the Dialect of the Lašva Valley. The basis of this work are two separate studies that have been published in the last two decades: The Bosniak dialectologist Refik Bulić wrote in 2013 a work entitled "Ekavsko-jekavski govori tešanjsko-maglajskog kraja" [The ekavian-jekavian dialect in the area of Tešanj and Maglaj]; ten years earlier (2003) the dialectologist Naila Valjevac published her study "Govor u slivu Lašve" [The dialect of the Lašva Valley]. The aim of this work is to examine the differences and similarities of these two dialects by three linguistic aspects: a) phonetic (articulation of the sounds), b) phonological (inventory of phonemes, distribution of allophones, phonological processes) and c) morphological (inflection and derivation of the words). After an introductory part with definitions and general framework, as well as the general introduction to Bosnian, Croatian, Montenegrin and Serbian dialects, the following sections are devoted to the phonetic and phonological comparative analysis of the Ekavian-jekavian dialect of Tešanj and Maglaj and the Dialect of the Lašva Valley. Thereafter, the focus is on the description of the morphological characteristics of the two dialects structured by nouns, pronouns, adjectives, numerals, verbs, adverbs, prepositions, conjunctions and particles. The subsequent chapter contains the results of the contrastive analyses, which are finally discussed in the summary. Furthermore, this work can be understood as the contrastive grammar of the Ekavian-jekavian dialect of Tešanj and Maglaj and the ikavian Dialect of the Lašva Valley.