The research entitled Vocabulary Mastery of Class A3 students of TK Aisyiyah Bustanul Athfal Somawangi, Mandiraja Regency, Banjarnegara Regency aims to describe vocabulary mastery in the speech of students of class A3 TK Aisyiyah Bustanul Athfal Somawangi, Mandiraja District, Banjarnegara. The type of research used is descriptive qualitative research. The data for this study were students of class A3 TK Aisyiyah Bustanul Athfal Somawangi, Mandiraja Banjarnegara District. The methods used in this research are: data presentation method, data analysis method, and data analysis presentation method. From the results of a study of 29 students consisting of 17 male students and 12 female students, the results of the oral vocabulary of class A3 TK Aisyiyah Bustanul Athfal Somawangi Mandiraja Banjarnegara Regency included general vocabulary consisting of nouns, verbs, adjectives, words adjectives, adverbs, and pronouns. Then, special vocabulary consisting of color words, time words, number words, popular sayings. The missing vocabulary is a special vocabulary which includes money words, swear words, and secret language words.