Cox Architecture originated in 1962 as a partnership between Philip Cox and Ian McKay. Their first buildings drew inspiration from the Australian farm and industrial vernacular and were widely regarded as the emergence of the first genuinely Australian contemporary architecture.

Most notable among the early works were St Andrews Boys Home at Emerald Hill near Sydney and the C.B. Alexander Agricultural College in the New South Wales Hunter Valley. The College was awarded the Royal Australian Institute of Architects Sulman Medal in 1964 and was described by the architectural historian J.M. Freeland as "epitomising the Sydney School of Architecture", which was an informal group of architects seeking to create direct responses to Sydney's unique topography and climate.

Through to the late 1970's, the practice's work was mainly domestic and school architecture as well as conservation of historic buildings. Philip Cox authored a number of books during this period which were influenced by a new appreciation of Australia's historic architecture, in particular Rude Timber Buildings of Australia, the Australian Homestead, Historic Towns of Australia, and The Australian Functional Tradition.

In 1977, the practice of Philip Cox and Partners undertook several projects in Canberra including the Embassy and Chancellery of Ireland, the National Athletics Stadium, and the National Indoor Sports and Training Centre. Although significantly different in type and scale from previous work, the two sports facilities embodied the same principles of structural integrity and climate response for which the practice was renowned.

In 1980, the firm began work on the new township of Yulara at Uluru (Ayers Rock), a project which simultaneously expanded the practice's size and enabled all of the formative principles of the practice to flourish in one of the most iconic of Australian environments. The Township was awarded the Royal Australian Institute of Architects Sir Zelman Cowen Award in 1984.

The remainder of the decade was dominated by significant public buildings for the 1988 Australian BiCentenary gaining the practice reputation, in particular for innovative structural solutions to stadia and exhibition centres. These include Sydney Football Stadium (now called Aussie Stadium) and Sydney Exhibition Centre.

Around this time, offices were opened in Melbourne, Brisbane and Perth, to complement those in Sydney and Canberra creating a true national practice.

During the 1990's, projects were acquired in Singapore and China from which an international reputation began to evolve. Offices were opened in Beijing, Shanghai, Singapore and Dubai generating opportunities to respond to different urban and environmental challenges.

By 2000, the practice had become one of Australia's largest. The range of projects types and sizes expanded considerably into office, retail, residential, resort and mixed use developments. Master planning became a significant focus of the practice, particularly for urban waterfronts and for tertiary education and research campuses both in Australia and internationally.  A number of international competitions were won including for Singapore Marina Bay Redevelopment and Singapore Management University.

Today, the scale and diversity of projects is managed by the directorship and team structure that maintains the philosophical principles and design quality which have been intrinsic to the Cox history.