* Tanzania: It is the official language of Tanzania.
* Kenya: It is one of the official languages of Kenya.
* Uganda: It is widely spoken in Uganda, especially in the capital, Kampala.
* Rwanda: Swahili is increasingly used in Rwanda, especially in government and business.
* Burundi: Swahili is used as a lingua franca in Burundi.
* Democratic Republic of Congo: Swahili is widely spoken in the eastern part of the DRC.
* Mozambique: Swahili is used in coastal areas and is becoming increasingly popular.
* Malawi: Swahili is gaining popularity in Malawi.
* Zambia: Swahili is used in some areas of Zambia, especially near the border with Tanzania.
It's important to note that while Swahili is widely spoken in these countries, it's not necessarily the primary language in all of them. For example, while Swahili is an official language of Kenya, the majority of Kenyans speak other languages like Kikuyu, Luo, and Luhya.
Swahili is also spoken by significant communities in other parts of Africa, as well as in parts of the diaspora.