Zoltán Kodály’s String Quartet No. 1 in C Minor is one of his earliest compositions. Kodály composed this as a tonal work, emulating the style used by nineteenth century composers. Kodály creates highly polyphonic textures and a complex harmonic language within the C minor tonality. Although this piece is considered tonal, Kodály deviates from the prototypical norms of tonal composition. As in most tonal music, harmonic progressions tend to support the overall tonal syntax. This includes chords, chord progressions, and key areas. The goal of this thesis is to categorize harmonic progressions in the first movement of Kodály’s String Quartet. In order for harmonic progressions to take place at the level of the chord, harmonic function must be present. I will break down the function of each chord by using Daniel Harrison’s scale degree theory from his book Harmonic Function in Chromatic Music. Some harmonic progressions follow a prototypical model that was utilized in common practice music. There are also chords in harmonic progressions that have an altered function—yet are still considered harmonic—which I will call “quasi-harmonic.” Lastly, some progressions are purely linear, and therefore the function is discerned on the macro level.