Murong De (Chinese: 慕容德; 336–405), name changed in 400 to Murong Beide (慕容備德), courtesy name Xuanming (玄明), formally Emperor Xianwu of (Southern) Yan ((南)燕獻武帝), was the founding emperor of the Chinese/Xianbei state Southern Yan. He was the son of Former Yan's founding prince Murong Huang (Prince Wenming) and younger brother to both Former Yan emperor Murong Jun (Emperor Jingzhao) and Later Yan emperor Murong Chui (Emperor Wucheng), and therefore was an imperial prince and general during the times of both states. After Murong Chui's son Murong Bao lost most of Later Yan's territory to Northern Wei, Murong De took troops under his own command south and established Southern Yan, which secured modern Shandong, but failed to expand further, and was destroyed by Jin Dynasty (265-420) after Murong De's death and succession by his nephew Murong Chao.
Murong De was born in 336 to Murong Huang and his concubine Consort Gongsun, who had previously given birth to his older brother Murong Na (慕容納). At that time, Murong Huang was the Duke of Liaodong and a vassal of Jin, although in 337 he claimed for himself the title of Prince of Yan (as Prince Wenming). As this was without Jin authorization (although Emperor Cheng of Jin would retroactively recognize this in 341 by creating him that title), this generally was considered the founding of the independent Former Yan state. When he was young, he was regarded as studious, handsome, and talented.