File:Flag Of The Mali Empire.png

English: The official flag or banner of the Mali Empire was probably just plain red; Al-Umari notes that Mansa Musa brought red banners with yellow symbols on it, sometimes translated to “yellow banners with a red background”, which brings to the misconception that the flag was actually a red flag with a yellow square.

However, reading Ibn Khaldūn's account, we only hear testimony about red banners without the yellow symbols — this plain red flag was noted both in a ceremony he described, and inside the court.

It's disputed whether it could've been really seen as an official flag or similar, however it might be also a plausible conclusion to note that adopting a banner was among the things Mali got from the Muslim world, choosing a red one in particular, sometimes putting yellow symbols on it.

SOURCES:

1) Gomez, M. A. (2019). African Dominion: A New History of Empire in Early and Medieval West Africa. United Kingdom: Princeton University Press. — p. 115

2) A History of Islam in West Africa - John Spencer Trimingham, University of Glasgow, 1970 — p. 79/80

3) Hamdun, S., King, N. Q. (1975). Ibn Battuta in Black Africa. London: Collings. — p. 50