Sakuma Nobumori (佐久間信盛; 1527-August 21, 1581) is a retainer of Oda clan. He has been also called Dewa no Suke(出羽介) and Uemon no I(右衛門尉)

He was born in Owari Province and served under Oda Nobuhide. Entrusted with the care of Oda Nobunaga when he was young, unlike other retainers who wavered over which side to take as the head of clan, Nobunaga or Oda Nobuyuki, Nobumori never changed his position as the royal retainer of Nobunaga always fighting on his side. For this royalty, he was treated as the most important retainer and he would fight in every important battles to be called Shirizoki Sakuma(退き佐久間), lit. retreating Sakuma for his cautious tactics. He had a success against Rokkaku clan and contributed to putting down Buddhist-based rebellions in Echizen Province and Nagashima Province . On 1572, he was a part of reinforcement to aid Tokugawa Ieyasu against Takeda Shingen. But unable to hold down Ieyasu, he fought in battle of Mikatagahara which ended in a crushing defeat losing Hirate Hirohide

On 1576, after hearing the report that Harada Naomasa died during a war against Honganji, Nobumori was chosen after Naomasa to lead and was supplied with troops from seven provinces, able to use the largest army of all retainers. Yet, while Akechi Mitsuhide, Shibata Katsuie and Hashiba Hideyoshi all gained advantages on the front they were tasked, faced with fearless Buddhist zealots, Nobumori made no progress at all. After ten years of battles, Nobunaga had the emperor make a truce to end the war on 1580.

On the same year, Nobunaga handed fifteen accusations of failures including past failures and the failure against Honganji to Nobumori and banished Nobumori and his son Sakuma Nobuhide to Koyasan to be a Buddhist monk. Nobumori died on 1581 at Totsugawa of Yamato Province. His posthumous names were 洞無桂巌 and 宗佑.

Nobumori's banishment has been widely called as the symbol for Nobunaga's cold bloodedness against even long time serving retainers as well as the inability and limit of Nobumori's ability. However, it has been recorded that from knowing Nobunaga since childhood, Nobumori too often critcized Nobunaga openly going against Nobunaga who disliked being opposed openly and had been spending too much time beside military matters while against Honganji repeatedly holding tea parties. He never devised any measure against Honganji even while the war was in a stalemate. So, it was not as harsh as it was, an entirely baseless accusation.