Kaiapoi was a rural New Zealand electorate, north of Christchurch in the Canterbury region of New Zealand from 1861 to 1946. It was represented by twelve Members of Parliament.

The electorate was centred on the town of Kaiapoi to the north of Christchurch. In the 1887 election, polling booths were in Kaiapoi, Clarkville, Rangiora and Woodend.^[1]

The electorate dates from 1861.^[2] Isaac Cookson was the first representative after winning the 1861. Cookson had previously represented the Christchurch Country electorate, which was abolished at the end of the term of the 2nd Parliament in 1960.^[3] Cookson resigned in 1863,^[4] and the resulting 1863 by-election was won by Robert Wilkin.^[5] Wilkin retired at the end of the parliamentary term and was succeeded by Joseph Beswick, who won the 1866 election, but resigned the following year.^[6][7]

The resulting 1867 by-election was won by John Studholme, who was confirmed at the 1871 election^[8] but resigned in 1874.^[9] He was succeeded by Charles Bowen in the 1875 by-election. Bowen was confirmed in the 1875 and 1879 elections.^[7] Bowen retired at the 1881 election.

Isaac Wilson was elected in 1881,^[10] but resigned before the end of the term due to failing health.^[11][12] Edward Richardson stood in the 16 May 1884 by-election. He was returned unopposed.^[13] Richardson won the 1884 and 1887 elections,^[14] and he retired at the end of the parliamentary term in 1890.^[15][16] In the 1887 election, his opponent was Richard Moore.^[1]

Moore was the successful candidate in the 1890 election.^[17][18] A conservative, he was defeated by David Buddo of the Liberal Party in the 1893 election.^[19] Moore in turn defeated Buddo in the 1896 election.^[17] In the 1899 election, Buddo defeated Moore again.^[19] This time, Buddo held the electorate until he was defeated in the 1919 election by David Jones.^[20] At the next election in 1922, Buddo defeated Jones. From 1925, his Liberal Party called itself 'National Party' for two years.^[21] Buddo retired in 1928.^[19]

Buddo was succeeded by Richard Hawke from the United Party in the 1928 election. He was re-elected in 1931,^[22] but lost the 1935 election against Labour's Morgan Williams.^[23] Williams held the electorate until it was abolished in 1946.^[24] Williams contested the St Albans in the 1946 election, but was defeated.^[23]