Since the release of Morten Lauridsen’s (b. 1943) celebrated O magnum mysterium (1994) and the meteoric success of Eric Whitacre (b. 1970) in the 1990s, expansive choral textures and non-functional tonal harmony have defined the sound of much choral output in the United States, dominating concert programs and album recordings. Their works are characterised by pandiatonic and extended harmonies, alongside thick, homophonic and antiphonic textures, in which voice parts are grouped together to form textural units. While Whitacre is the only composer to write exclusively in this style, elements of this compositional palette can be found in works by many contemporary choral composers developing and expanding on the technique. Despite the widespread popularity of this style of composition, its proponents have received little scholarly attention. The term ‘New Transcendentalism’ has been applied to the style, though it has not been established in research. This thesis presents analysis of select works by composers of New Transcendental music with a case study on Whitacre in order to identify the common musical features that link their works and to firmly establish New Transcendentalism as a term for this idiosyncratic style. Alongside interviews with the composers under review, a combinative approach incorporating Patricia Howland’s Integrated Parametric Structure Analysis and Critical Score Analysis is presented for illuminating the structure and compositional features of New Transcendental works, providing a basis for future scholarship on this emerging style of choral composition. Through comparative analysis of the music of Whitacre alongside works by Dale Trumbore (b. 1987), Jake Runestad (b. 1986), Dan Forrest (b. 1978), Marques L.A. Garrett (b. 1984), and Susan LaBarr (b. 1981), alongside interviews with the composers under review, this research highlights developments in New Transcendentalism beyond its two epochal figures, inviting further research into this new approach to choral composition.