Happy-Go-Lucky Days (どうにかなる日々, Dōnika Naru Hibi) is a Japanese manga series by Takako Shimura. It was serialized in Ohta Publishing's manga magazine Manga Erotics F from 2002 to 2004 and was collected in two large-sized tankōbon volumes. The manga is a collection of short episodes that depict slightly eccentric love stories and mundane daily life in a matter-of-fact manner with a unique tempo and delicate psychological descriptions. Most of the episodes in the collection have direct sexual depictions, although they are drawn in a light-hearted way. The manga's title comes from the book Herahera Botchan by Kō Machida.

An anime film adaptation produced by Liden Films Kyoto Studio and directed by Takuya Satō premiered on October 23, 2020.