Tiger Inn (or "T.I." as it is colloquially known) is one of the eleven active eating clubs at Princeton University in Princeton, New Jersey. Tiger Inn was founded in 1890 and is one of the "Big Four" eating clubs at Princeton (the others are The Ivy Club, University Cottage Club, and Cap and Gown Club), the four oldest and most prestigious on campus. Tiger Inn is the third oldest Princeton Eating Club. Its historic clubhouse is located at 48 Prospect Avenue, Princeton, New Jersey, near the Princeton University campus. Members of "T.I." also frequently refer to the club as "The Glorious Tiger Inn."

The Tiger Inn clubhouse is the oldest of the Princeton Eating Club houses. It is both architecturally distinct, built in the Tudor style, and historically notable. "The Clubhouse is designed in the timbered style of the 15th century and modeled especially after an old inn in Chelsea.". The clubhouse was built in 1895 for an original club membership of 30 undergraduates. The clubhouse has been in continuous use since the facility first opened. The architect for the clubhouse's original plan was G Howard Chamberlain. According to The Tiger Inn's official history, "Princeton myth [also] credits [the original plans for the clubhouse] to Howard Crosby Butler, Class of 1892 (a [Charter] member of Tiger Inn and Princeton's first Professor of architectural history)." The clubhouse's central hall was filled with massive antique furniture presented to the club by Mrs. Thomas Harrison Garrett (the former Alice Dickerson Whitridge (1851–1920), "the widow of a Princeton trustee and mother of three of Princeton's most prominent graduates of the 1890s" Robert Garrett, John W. Garrett, and ???); these furnishings remain in use to this day. The funding for the original clubhouse, the land, and the club's other furnishings were provided by the club's membership, although all at the time recognized the extraordinary support and contributions of the Garrett family.

Renovations to the clubhouse have continued since it was built in 1895. During 1922–1923 a room was added to the left of the front door and the second floor was remodeled; the second floor alterations were never used for their intended purpose as members quickly converted the new portion of the second floor space to a card room. In the fall of 1926 the clubhouse was substantially improved; during the six weeks of these alterations club members were required to take their meals at the surrounding clubs. By 1928 the kitchen had been moved to the south of the building. The changes to the clubhouse from 1926 to 1928 were well timed as this coincided with an expansion of the membership. The financing of the renovations placed Tiger Inn on the firm financial footing it would need to survive the Great Depression.

The distinctive clubhouse has recently undergone renovations, improvements and enlargements as part of its “21st Century Expansion and Renovation Project,” for which the commissioned architect was Connolly Architecture, Inc. The project was completed with the formal dedication of the new club facilities on the weekend of 11-11-11. Funded entirely by the club's alumni, the expanded facilities include a new dining hall and improvements to the spaces normally reserved for social events. The new facilities provide a more suitable building to serve the club's Active Membership, now up from 26 to over 150 in any given year, and club alumni exceeding 2000 in 2012. Fundraising for the completed project continues.

Tiger Inn is a selective club, meaning membership is awarded after successful completion of a process called bicker. During bicker, prospective members interact with current members who then convene to vote on whether the prospective members should "receive a bid," or be invited to join the club.

The club has designated its 26 original founding members as "Charter Members:" at the time of the club's founding, these members were known within the Princeton University community as "The Sour Balls." The Active Membership is that portion of membership that uses the clubhouse on a daily basis and is composed principally of Princeton undergraduates, although graduate students have also been active members from time to time. Alumni Members frequently return to the Tiger Inn. The club also has two honorific categories of membership to recognize and honor those who have had a positive and notable association with the club, whether as members of the Princeton University community or as individuals whose principal affiliation with the Princeton community is their association with the Tiger Inn.

Tiger Inn's membership was once described by F. Scott Fitzgerald in This Side of Paradise (1920) as "broad-shouldered and athletic, vitalized by an honest elaboration of prep-school standards." In a 1927 essay on Princeton for the magazine College Humor, Fitzgerald elaborated: "Tiger Inn cultivates a bluff simplicity. Its membership is largely athletic and while it pretends to disdain social qualifications it has a sharp exclusiveness of its own."

Fitzgerald's comments were written during his time at Princeton University, when the membership of each of the Eating Clubs was male only. Women were not accepted as undergraduates at Princeton until 1969. Debate over co-ed Eating Club membership abounded from 1969 until 1991. In 1979, undergraduate Sally Frank filed suit against then all-male clubs Ivy Club, Cottage Club, and Tiger Inn for gender discrimination. While Cottage chose to coeducate during the intervening years, Ivy Club and Tiger Inn were forced to become co-ed organizations in 1991, after their appeal to the U.S. Supreme Court regarding Frank's lawsuit was denied. The New Jersey Supreme Court had ruled in Frank v. Ivy Club that the failure to open membership to women violated the state's anti-discrimination statute.