The Sicangu are one of the seven oyates, nations or council fires, of Lakota people, an Indigenous people of the Northern Plains. Today, many Sicangu people are enrolled citizens of the Rosebud Sioux Tribe of the Rosebud Indian Reservation and Lower Brule Sioux Tribe of the Lower Brule Reservation in South Dakota.

Many Sičhą́ǧu people live on the Rosebud Indian Reservation in southwestern South Dakota and are enrolled in the federally recognized Rosebud Sioux Tribe, also known in Lakȟóta as the Sičhą́ǧu Oyáte. A smaller population lives on the Lower Brule Indian Reservation, on the west bank of the Missouri River in central South Dakota, and on the Pine Ridge Indian Reservation, also in South Dakota, directly west of the Rosebud Indian Reservation. The different federally recognized tribes are politically independent of each other.

The Sicangu Lakota are known as Sičhą́ǧu Oyáte in Lakȟóta, which translates to "Burnt Thighs Nation". Learning the meaning of their name, the French called them the Brûlé, also Brulé, meaning "burnt". The name may have derived from an incident where they were fleeing through a grass fire on the plains.

The term "Sičhą́ǧu" appears on pages 3 to 14 of Beginning Lakhóta.

"Ká Lakȟóta kį líla hą́ske. 'That Indian (over yonder) is very tall.'"
"Hą, hé Sičhą́ǧú. 'Yes, that's a Rosebud Sioux.'"

It appears to be a compound word of the Thítȟųwą Lakȟóta dialect, meaning "burned thigh".

Together with the Oglála Lakȟóta, who are mostly based at the Pine Ridge Indian Reservation, they are often called Southern Lakȟóta.

They were divided in three great regional tribal divisions: