The Olsen twins are fraternal twins who have appeared in television and films since infancy. Since then, they have attained international fame through numerous television programs, films, interviews, as well as commercial endorsements. As a rule, they appear together, and have filmed movies worldwide, including in London, Sydney, Paris, New York City and Rome.

They are reported to be worth $150 million each. The twins were named as the "Most Powerful Young Women in Hollywood" by the industry publication Hollywood Reporter.

Shortly after the end of Full House, they returned to the entertainment industry, riding the momentum of their role on Full House by heavily merchandising their image. Taking the world of tweens by storm, their names have become a very profitable industry, with their likeness seen in clothes, fragrances, magazines, movies, posters, and even video games like Mary Kate and Ashley's Magical Mystery Mall.

Today, Mary-Kate and Ashley are popular figures in today's teen market, following along the lines of such Hollywood child stars as Shirley Temple, Ron Howard and Macaulay Culkin among others. They were ranked at number three on the VH1 program 100 Greatest Child Stars.

They starred in the video series The Adventures of Mary-Kate & Ashley and the ABC show Two of a Kind (now rerun on ABC Family), as well as ABC Family's So Little Time. They also have their own book series. So Little Time was panned by critics and disappointed fans; the show is basically a single-camera comedy show with a laugh track.

In 2004 Mary-Kate and Ashley surprised many when they announced that they would be attending college after graduating high school. Most child and teenage actors usually choose to pursue acting full time after graduating from high school, with few (such as Brooke Shields, Jodie Foster, Julia Stiles, and Natalie Portman) choosing to further their education. They both studied at New York University at the Gallatin School of Individualized Study until Mary-Kate took a break in 2005 and moved back to California. She decided to stay in the west coast and pursue more individualized work with their company, DualStar. Ashley, still in NY, remains in contact with her sister.

The twins received a star on the Hollywood Walk of Fame on April 29, 2004. They are the youngest celebrities to receive this honor.

They have also been on the Forbes.com The Celebrity 100 list since 2002.

Both Mary-Kate and Ashley have been tapped as the faces of upscale fashion line Badgley Mischka

Mary-Kate is not the only twin receiving personal public attention. Ashley filed a $40 million lawsuit against tabloid magazine National Enquirer for printing a headline reading "Ashley Olsen Caught In Drug Scandal," with a story accompanied by an unflattering photo of Ashley with her eyes half-closed. The lawsuit stated that the photo was clearly used to create a misimpression that Olsen was drugged. Ashley completely denies the accusations and said that she has not and does not use or sell illegal drugs. The suit consisted of $20 million in libel damages and $20 million in false light invasion of privacy damages. Per her suit, Ashley Olsen and her lawyers believe that "freedom of the press is a valuable right, but it is not a license for gossipy tabloids to tar and feather innocent celebrities and destroy their reputations and businesses for the rags' profits.