Maeda Toshimasu (前田 利益?, 1543? - 1612), better known as Maeda Keiji (前田慶次?) or Keijirō (慶次郎), was a Japanese samurai of the Sengoku Period through early Edo Period.
Toshimasu was born in the village of Arako (present-day Nakagawa-ku, Nagoya), Toshimasu was born to the Takigawa Clan, originally the son of Takigawa Kazumasu. He was adopted by Maeda Toshihisa, the older brother of Maeda Toshiie. Toshimasu served under Oda Nobunaga along with his uncle. Toshimasu was originally intended to inherit Maeda family headship; however, after Oda Nobunaga replaced Toshihisa with Toshiie as Maeda family head, he lost this position. Perhaps because of this loss of inheritance, Toshimasu is well known for quarreling with his uncle.
In 1581, Toshimasu was under the command of his uncle, and made a reputation for himself through conflicts within Noto Province and was rewarded with 5,000 koku. During the Battle of Komaki-Nagakute three years later, Toshimasu went to Sassa Narimasa's rescue when he was attacked at Suemori Castle. While in Kyoto, Toshimasu met and befriended Naoe Kanetsugu, Uesugi Kagekatsu's karō. The two became close friends, and Toshimasu agreed to join Kanetsugu in the Uesugi clan's invasion of Aizu. The invasion failed, and Keiji was appointed to led the rear guard during the retreat. Riding his horse Matsukaze into battle and brandishing a two-pronged spear, he made a splendid show of force. Due in part to Toshimasu's actions, the Uesugi forces were able to retreat largely intact.