Ōkubo Tadaaki (大久保 忠顕, December 5, 1760 – September 23, 1803) was the 6th daimyō of Odawara Domain in Sagami Province (modern-day Kanagawa Prefecture) in mid-Edo period Japan.
Inclement weather led to crop failures, including the Great Tenmei Famine, which severely curtailed traffic on the Tōkaidō highway connecting Edo with Kyoto.
As one of the major post stations on the Tōkaidō, this created an economic crisis for the town residents.
Although Tadaaki responded with the usual restrictions on spending in an effort to economize of the domain's tax revenues, his efforts were undermined by rampant inflation, and demands from the Tokugawa shogunate to strength coastal defenses against possible incursions of foreign vessels.
Takaaki was married to a daughter of Nakagawa Hisasada, daimyō of Oka Domain in Bungo Province.