Genna (元和^?) was a Japanese era name (年号,, nengō,^?, lit. "year" name") coming after Keichō and before Kan'ei. This period spanned the years from July 1615 to February 1624. The reigning emperor was Go-Mizunoo-tennō (後水尾天皇^?).

The Siege of Osaka was a series of battles undertaken by the Tokugawa shogunate against the Toyotomi clan, and ending in that clan's destruction. Divided into two stages (the "Winter Campaign" and the "Summer Campaign"), and lasting from 1614 through 1615, the siege put an end to the last major armed opposition to the establishment of an enduring Tokugawa shogunate. The end of this period of fighting is also sometimes called the Genna Armistice (元和偃武,, Genna-enbu^?) because the era name was changed from Keichō to Genna immediately following its ultimate resolution.

By order of Tokugawa Ieyasu, the era name of Emperor Xianzong of Tang China was adopted.