Honoria Gray began law school in 1969 aged 40 and was admitted to the bar in 1976. According to statistics published by the Auckland District Law Society, in 1980 only 26.3% of law graduates were women although by the early 1990s the number of female graduates began to exceed those of their male counterparts. Barriers still exist, however. In 2013, while 61.8% of new admissions to the profession were women, 'the same cannot be said for more senior ranks.'

Gray specialised in criminal law and Maori land law - she was one of New Zealand's pioneering lawyers in the latter field.