Lia Marie Johnson is an American teen actress and internet personality notable for appearing in a various web series created by the Fine Brothers, including the Emmy-winning web series Kids React, and for her own vlogging and social media output. In 2012 her personal YouTube channel, "Lia Marie Johnson", was reported to have received 13 million views. In 2014, this was reported to have increased up-to 39 million views and 705,000 subscribers, while her Instagram account was followed by 1.1 million followers. In an Adweek profile she was referred to as one of "12 of the biggest young stars on YouTube".

Johnson's YouTube account was created on December 17, 2007, with early videos uploaded by her mother which featured her performances at talent shows, and church recitals. After two years, Johnson began to control the output of the channel, creating content that has come to include personal commentary, sketch comedy, and musical performances. In 2010, Johnson began to work with the Fine Brothers as a recurring member of their Kids React series. This exposure increased the traffic to her own channel and became an early source of her online fame.

In 2011, Johnson was added to the recurring cast of the spin-off series "Teens React", and in 2014 was moved again to the newly established "YouTubers React", which featured herself and various well known YouTube personalities. In 2014, Johnson appeared at the Nickelodeon Kids' Choice Awards, and starred in Terry the Tomboy: The Movie, a spin-off film based on the eponymous character she portrays on the Nickelodeon sketch comedy series, AwesomenessTV. She can currently be seen on YouTube singing with Alejandro Luis Manzano of Boyce Avenue presenting a new edge on a cover of the single, "Latch" by Disclosure.

YouTube Sensations,