Also known as: Ise Ujitsuna (伊勢氏綱)

Houjou Ujitsuna was born eldest son and heir of Ise Moritoki. He became the second head of the Later Houjou Clan in 1518 upon the retirement of his father, though it is possible that his father had transferred the rule of the clan to him long before or ruled in concert with him.

Born Ise Ujitsuna, he changed his family name to Houjou after the line of regents of the Kamakura shogunate and also adopted their family crest of three fish scales (three triangles forming a large triangle) in 1523. He posthumously gave his father the name of Houjou Souun.

In Souun's time, the Houjou main castle was Nirayama Castle in Izu Province. Ujitsuna made Odawara Castle in Sagami his stronghold.

As clan head, Ujitsuna greatly expanded the Houjou Clan's influence in the Kantou. He took both Edo Castle (1524) and Kawagoe Castle (1537) in Musashi from the Uesugi Clan. He initially formed an alliance with Imagawa Ujichika in Suruga, but it broke apart upon an alliance between Suruga and Kai.

Ujitsuna collapsed and died of illness in the summer of 1541 during the long war with Suruga that followed. He was succeeded by his eldest son and heir, Houjou Ujiyasu.