Charles' Clarence House office says his speech will be given in the second week of the conference, when heads of government start to gather.
Clarence House said Tuesday he was invited to the 192-nation summit by the Danish government.
Charles is well-known in Britain for his environmental advocacy. He is due to address expert delegates and non-governmental organizations.
Britain's Climate Change Secretary Ed Miliband welcomed Charles' presence at Copenhagen, saying he has shown dedication to raising global awareness of the threats of climate change. The conference starts Monday.