johnnie-O is a clothing company started in 2004 by John O'Donnell.

This company combines "east coast preppy" with "west coast 'dude'" to a create a lifestyle brand referred to as west coast preppy. They use a surfer with his board as their logo which immediately triggers images of an active but casual outdoor way of life in our social consciousness. The unique style of the johnnie-O clothing line has made it increasingly popular among golf and entertainment circles. Actors including John's brother Chris O'Donnell have appeared on popular television shows wearing johnnie-O apparel.

The presence of the brand is apparent in various magazines ^{[4] [5]} and websites. ^[6] The company makes numerous charitable contributions to organizations such as Autism Speaks, The Brees Dream Foundation, Juvenile Diabetes Research Foundation, Surfrider Foundation, Mobile C.A.R.E. Foundation, Children's Hospital of Orange County, Allendale Shelter Club, among others.