Orange's 5G coverage will eventually extend to 30% of the southern African nation's population, including those living in Gaborone and Francistown, Botswana's two largest cities.
Coverage will be extended to other cities early next year, the company said.
Despite declining costs, the majority of Africans still cannot afford 5G-capable mobile handsets.
But Orange is focusing on 5G as a way to provide fast internet in Africa, where the continent's low population density makes the installation of fiber-optic infrastructure unprofitable.
"For us the main use case is fixed wireless access, meaning internet at home," Nene Maiga, CEO of Orange Botswana, told journalists ahead of the launch.
Africa and the Middle East, where Orange operates in 18 countries, account for over 60% of the company's total mobile customers and 6.4 billion euros ($6.6 billion) in revenue.
The region currently counts more than 44 million 4G customers.
Orange's Middle East and Africa CEO Jerome Henrique said the company was targeting 5G rollouts in around half a dozen countries in 2023, most likely starting with Jordan.
"There's already an agreement with the government on the conditions for launching 5G in Jordan. And most probably Ivory Coast and Senegal shall follow, but we're still discussing about regulatory conditions," he said.