Ariella Käslin (anglicised Kaeslin; born 11 October 1987) is a Swiss former artistic gymnast.

[3] Käslin organized a training boycott in 2007 with three of her teammates due to abusive behavior from the national coach at the time.

[4] In 2008, 2009 and 2010, Käslin was voted by the Swiss public as "Swiss Sportswoman of the Year"; only cyclist Tony Rominger (1992, 1993, 1994) had previously achieved three consecutive "Sportsman of the Year" awards in Switzerland.

In 2009, she became European Champion on the vault, as well as taking home a bronze medal in the all-around final.

She then followed up this success with a silver medal on the vault at the 2009 World Championships.