In 1933 Miss Lenthall (Headmistress 1903-1934) decided to introduce a House system. The purpose was to promote healthy competition and friendly rivalry amongst the girls and to encourage and recognize effort in work, sport and conduct. Miss Lenthall and her staff decided on the names of the first three Houses: Barker, Bronte and Casterton. Each House was to have House Officials comprising a President (staff member, now Head of House), a Captain and three Lieutenants, later replaced by one House Vice Captain.
In 1987, due to an increase in the School population, two more Houses were introduced by Miss Patterson. These were named Hulme-Moir and Sutherland. A design competition was held to select the badges for each House.

Barker House
Motto: We attain by attempt
Barker House was formed in 1933 and named in honour of Mrs Jane Barker, wife of the first Bishop of Sydney. Mrs Barker's vision was to provide for the education of daughters of the clergy. She founded St Catherine's in 1856, modelled on Casterton School in England. Barker's colour is green.

Bronte House
Motto: He who conquers himself conquers all
Bronte House was formed in 1933 and named in honour of Charlotte Bronte. Bronte was originally called 'Charlotte Bronte House' hence the CB on the badge. Charlotte Bronte based her novel Jane Eyre on Cowan Bridge School, the predecessor of Casterton School. Bronte's colours are blue and gold.

Casterton House
Motto: Honour in all things
Casterton House was formed in 1933 and named in honour of Casterton School in the Lake District of England, where Jane Barker grew up. The school attended by the Bronte sisters was only a few miles from Mrs Barker's family home. Both schools were originally founded for the daughters of clergy. Casterton's colours are red and blue.

Hulme-Moir House
Motto: Understanding through heart and mind
Hulme-Moir House, formed in 1987, was named in honour of Bishop and Mrs Hulme-Moir. Bishop Hulme-Moir was Chairman of St Catherine's School Council. The badge features Penny Hensford's design which symbolises the writings of Mrs Hulme-Moir, an Old Girl (1917-1924). The House colour is purple, a bishop's official colour.

Sutherland House
Motto: Success through unity and courage
Sutherland House was formed in 1987 and named in honour of Dame Joan Sutherland OM., AC., DBE., an Old Girl of St Catherine's (1934-43) who was made a Dame of the British Empire for services to Music in 1979. The badge features Roberta McWilliams design of a lyre to symbolise music. The House colour is pale blue.