If you're looking for manga similar to Gintama, you might like these titles. All recommendations are made by Anime-Planet users like you!
Life can be difficult in high school. Luckily for Kaimei Gakuen High there is a club called the Sket Dance. Defined as the "Campus Support Group," this club is dedicated to solving the problems of their school. However, due to the lack of important jobs, the Sket Dance is often overlooked and mostly used to do boring handiwork tasks rather than solving actual problems. But when they do get a job, like finding the culprit of bullying or taking care of a classmate's pet monkey, they are able to show their true skills. The Sket Dance has three members: former delinquent and violent Himeko, information and technology-loving otaku Switch, and atypical leader Bossun. Whether it's solving problems or just fixing up the storage shed, the Sket Dance will always try their best and give each job their all!
Both Gintama and Sket Dance are centered around the same idea. A group of three people, which include a violent girl, a nerdy boy, and an atypical useless leader, take on odd jobs and services for the help of other people. You can't get more similar than the same plot structure. If you like one you will like the other.
Apart from the surprisingly similar characters from both series, Sket Dance and Gintama are very similar to each other; although Sket Dance has a possibly more mistery than the more light-hearted and absurd sci-fi setting of Gintama, both manga relate around a group of free-lancers with unique members, such as overtly violent girls, only apparently useless leaders that turn out to actually have quite amazing skills and so on, all with a heavy use of humor and a plot which remains hidden behind the various gags...
Both involve a group of three people trying to help out others. One is the boss who seems like a good-for-nothing but pulls through at the end. The other is an otaku and the last is a girl with fierce strength. Both are comedic and have parodies. They have similar feels.