Keishi Nishikida is a Japanese manga artist known for his work on several romantic comedy series, often in collaboration with other writers. His professional credits include both illustrating stories written by others and creating his own original narratives.

Nishikida first gained recognition as the illustrator for My Wife is Wagatsuma-san, a manga written by Yuu Kuraishi. The series was serialized in Kodansha's Weekly Shonen Magazine from September 2011 to September 2014, spanning 13 collected volumes. The story follows a high school student who can time-slip ten years into the future, where he discovers he is married to the most popular girl in school.

Nishikida later took on the role of both writer and artist for Kiss shite Kurenakya Shinjau, a romantic comedy manga serialized in Kodansha's Magazine Pocket from March 2019 to June 2020. The series was collected in three volumes and features a premise involving a rare illness requiring regular kisses for survival.

More recently, Nishikida has served as the artist for Grapara!, with story by Airi Katsura. This manga began serialization in Kodansha's Magazine Pocket service in August 2023. The story centers on a gravure idol and her devoted fan who end up living together after he saves her from a stalker, leading to a slightly risqué love comedy as he works to protect her. In May 2025, it was announced that Grapara! would receive a live-action television series adaptation, scheduled to premiere in July 2025.