樂天

樂天, 楽天, 乐天	or 낙천, meaning "optimism", may refer to:


 * Bai Juyi, courtesy name Letian (樂天), Chinese musician, poet, and politician during the Tang dynasty
 * Jungjong of Joseon, courtesy name Nakcheon (낙천, 樂天), ruler of the Joseon dynasty of Korea
 * Optimism (樂天), 2001 album by Hong Kong singer Louis Koo
 * Rakuten (楽天), Japanese technology conglomerate