Sphinx, the senior honorary, was founded at The Ohio State University in 1907 and is the oldest honorary on campus.

Founded as a men's class honorary, Sphinx inducted its first female members in 1978. Since its inception, Sphinx has remained one of the most selective and prestigious organizations at The Ohio State University. The organization recognizes up to 24 outstanding juniors during spring quarter by "linking them into Sphinx." Criteria for selection include leadership, scholarship, character and service while attending The Ohio State University. Sphinx members are individually active in numerous student and community organizations while the group also takes part in many campus events, volunteers with local organizations and participates in quarterly advances.

Sphinx Plaza, which is located just north of the Main Library, was constructed in 1982 to commemorate the honorary's 75th anniversary. Sphinx Grove, which is located on the West side of the Longaberger Alumni House, was planted in 1995. It consists of 24 Scarlet Oaks to represent the 24 active student links chosen each year. Those physical places are an affirmation of Sphinx's commitment to enhancing and promoting the interests of The Ohio State University.

The objectives of SPHINX, as established by its founders in 1907, are
• to recognize and honor students who have shown success in various fields of endeavor
• to create a bond of fellowship in which each individual will use his or her abilities to enhance and promote the best interests of The Ohio State University.