Waltham is an inner suburb of Christchurch, New Zealand, located two kilometres southeast of the city centre. State Highway 73, part of Christchurch's ring road system, runs through the suburb, as does the Heathcote River and the Christchurch - Lyttelton rail corridor. The Christchurch gasworks was located at the inner boundary of Waltham until its closure ca. 1980.
Waltham was originally part of the Sydenham borough and was incorporated into the City of Christchurch in 1903. It is named for the village of Waltham, Lincolnshire in England.
The suburb (as defined by the Statistics New Zealand meshblock) is about 1 km², much of which is occupied by light and heavy industry - the residential population is less than 1000. The suburb ranks below average in income and high in unemployment. Amenities include Jade Stadium, Christchurch's international rugby and cricket venue, and Waltham Lido pool.