Morning Musume (モーニング娘。; Morning Girls), currently known as Morning Musume '24 (モーニング娘。'24, read as Morning Musume Two-Four), is the lead group of Hello! Project. The group was formed in 1997 on a talent show called ASAYAN. It quickly became, and currently is, one of Japan's top all-girl groups with a number of hit records and albums. On merchandise using the English name, the group's name is commonly stylized with a kuten (。) as it would appear in the Japanese name.

The group is known for their ever-fluctuating line-up, with graduations and auditions held nearly every year. Tsunku was previously responsible for the composition of the majority of their songs and lyrics, production of their CD-sleeve covers, designing of their costumes and make-up, and their live shows until late 2014, when he resigned from his position as Hello! Project's general producer. He continues to work with Morning Musume, but only as their sound producer.

Currently, they are one of the most successful Japanese idol girl groups, holding the record for the second highest overall single sales (of a female group) on the Oricon charts as of January 2012,as well as the record for the most top ten singles with 66 titles as of October 2018 and the most top ten albums with 18 titles as of March 2019 Morning Musume is also the biggest DVD seller in the female group category in Japan. Their combined CD and DVD sales exceed 23 million copies in Japan alone.

In recent years, the group has been making a concerted attempt to break into new markets in Asia, Europe, and the US, performing at expos worldwide.