Okabe Motonobu (岡部 元信, d. April 25, 1581), also known by his common name Gorobei, was Japanese samurai of the Sengoku period, in the service of the Imagawa clan. The second son of Okabe Chikatsuna, he became a senior retainer of the Imagawa, following in his father's footsteps. After his lord Imagawa Yoshimoto was killed at the Battle of Okehazama, he kept fighting and even retrieved his lord's corpse. Following the clan's collapse he switched allegiance to the Takeda clan and defended Takatenjin Castle. He died in 1581 when he was attacked by Tokugawa forces under Honda Tadakatsu.