This thesis explores the domestic designs produced in Canterbury, New Zealand, by the architectural firm of Collins and Harman between 1883 and 1927. Architects John James Collins (1855 – 1933) and Richard Dacre Harman (1859 – 1927) were partners in the firm founded in Christchurch by William Barnett Armson (1833 – 1883) in 1870. Like many New Zealand architects practicing at the turn of twentieth century, Collins and Harman worked amidst a climate of major social and economic transformation, yet they managed to navigate these transitions with their personal connections and respected positions within the local architectural profession. From Collins and Harman’s surviving architectural drawings and office records, the firm’s ability to design residences in accordance with its clients’ wishes is evaluated. The methods with which they carried out designs, transacted business and secured future clients are also considered. The social standing of the firm’s clientele is emphasised to highlight the tight-knit nature of architectural patronage in Canterbury during this period. In order to assess the firm’s contribution to the development of domestic architecture in New Zealand, the local architectural profession, the firm’s reputation, and the effects that its built designs had on its clients and the local community are also investigated. While their major public and commercial designs are included in general surveys of New Zealand architecture, Collins and Harman tend to be overlooked as domestic architects in comparison with better-known contemporaries such as Samuel Hurst Seager and Cecil Wood. In catering to the requirements of a diverse clientele, the firm adopted varied approaches in its designs, which illustrate a more complex evolution than the linear progression usually found in standard architectural historical methodologies. Divided chronologically into four distinct periods, the thesis focuses on key commissions to chart the firm’s development over forty-four years within the context of the evolution of domestic architecture in Canterbury. The diversity in its domestic work engendered by the firm’s professionalism demonstrates that Collins and Harman made a substantial and vital contribution in the development of domestic architecture in Canterbury.