This is a list of postal codes for the province of Ontario in Canada with the prefix K.
- K1A - Ottawa
- K1B - Ottawa
- K1C - Ottawa
- K1E - Ottawa
- K1G - Ottawa
- K1H - Ottawa
- K1J - Ottawa
- K1K - Ottawa
- K1L - Ottawa
- K1M - Ottawa
- K1N - Ottawa
- K1P - Ottawa
- K1R - Ottawa
- K1S - Ottawa
- K1T - Ottawa
- K1V - Ottawa
- K1W - Ottawa
- K1X - Ottawa
- K1Y - Ottawa
- K1Z - Ottawa
- K2B - Ottawa
- K2C - Ottawa
- K2E - Ottawa
- K2G - Ottawa
- K2H - Ottawa
- K2J - Ottawa
- K2K - Ottawa
- K2L - Ottawa
- K2M - Ottawa
- K2P - Ottawa
- K2R - Ottawa
- K2S - Ottawa
- K2T - Ottawa
- K2V - Ottawa
- K2W - Ottawa
- K4A - Ottawa
- K4B - Ottawa
- K4C - Ottawa
- K4M - Ottawa
- K4P - Ottawa
- K6H - Cornwall
- K6J - Cornwall
- K6K - Cornwall
- K6T - Brockville
- K6V - Brockville
- K8A - Pembroke
- K8B - Pembroke
- K8N - Belleville
- K8P - Belleville
- K8R - Belleville
- K9H - Peterborough
- K9J - Peterborough
- K9K - Peterborough
- K9L - Peterborough
See also: List of postal codes in Canada
