Man'en (万延) was a Japanese era name (年号, nengō; lit. "year name") after Ansei and before Bunkyū. This period spanned the years from March 1860 through February 1861. The reigning emperor was Kōmei-tennō (孝明天皇).

The new era name is derived from an hortatory aphorism to be found in The Book of the Later Han: "With 100,000,000,000 descendants, your name will forever be recorded" (豊千億之子孫、歴万載而永延).