Khama succeeded former President Festus Mogae as president in 2008 after serving as Vice President since 1998. He was elected for a full five-year term in 2009 and re-elected in 2014 for his final second term.
The former military commander will also be replaced as the leader of the Botswana Democratic Party (BDP) by his vice president who was elected in July to lead the ruling party.
Vice President Mokgweetsi Masisi will serve as interim president until the election in 2019 which will see four main opposition parties standing as a coalition to topple the ruling party which has been in power since 1966.
Ian Khama says the country can achieve its vision by coming together to build the country.
“While we will undoubtedly continue to confront significant challenges, when we place the interests of Botswana first we shall find the strength to overcome all obstacles,” he said.