This article concerns the String Quartets of Erik Tulindberg (1761–1814), who was the first known Finnish composer. Tulindberg was musically active primarily in the late 1770s and early 1780s, when he was studying at the Royal Academy of Turku (Kunglika Akademien i Åbo). He was respected as a skilful violinist and a chamber musician, playing in the Academy’s orchestra on ceremonial occasions and giving public concerts. Tulindberg’s compositional oeuvre comprises two Violin Concertos, six String Quartets and a few works for solo violin. The corpus of Tulindberg’s String Quartets is approached from two perspectives, namely conventional strategies of the Classical style on one hand, and Tulindberg’s recurrent choices as attributes of his personal musical language on the other. Widely used analytical tools are applied in studying the corpus, and the Quartets are compared with certain works that originate in the same period and reside in Tulindberg’s archive. The theoretical framework includes writings that focus specifically on describing the compositional strategies used in Classical and Pre-Classical music, the authors including James Hepokoski and Warren Darcy, Graham Hunt, William Caplin, Poundie Burstein and Danuta Mirka, among others. The discussion covers 1) the overall structure, the key design and cadences in the opening movements, all of which are in sonata form; 2) the essential harmonic traits; and 3) surface characteristics and expressive means such as topics, melodic figuration and instrumental writing. The analysis reveals that Tulindberg adopted the commonly used strategies and main expressive means of the Classical style. The attributes of his musical language include traits such as the constant use of extended modal mixture, enthusiasm for a varied rondo-form and frequent violoncello solos in the upper register. Although the String Quartets are conventional in structure, each one is individual in its construction. The stylistic correspondence between the works and those of composers such as Joseph Haydn, Luigi Boccherini and Ignace Pleyel, shows his thorough understanding of the music written by his contemporaries.