The fraternity originated on December 17, 1927 with the initiation of 13 men into the Delta Epsilon Chapter of Phi Sigma Chi, a fraternity for business students. With membership increasing rapidly, the brothers felt the need to leave their dwelling at 212 South Darling Street. The purchased a house one block away at 115 South Darling Street, formerly owned by Professor and Mrs. Fred Starr, known as Guidi Hall. This is currently the chapter's home address.

In 1934, Tri-State College decided that all social fraternities should make collegiate connections. In compliance, Delta Epsilon Chapter of Phi Sigma Chi became Iota Chapter of Sigma Delta Rho. After two years, Tri-State College changed their policy and Iota Chapter of Sigma Delta Rho re-affiliated with Phi Sigma Chi.

In 1948, the members of Phi Sigma Chi sought to improve themselves by seeking affiliation with Alpha Gamma Upsilon. On May 8th, 1949, the Delta Epsilon Chapter of Phi Sigma Chi became Lambda Chapter of Alpha Gamma Upsilon.

The members managed the fraternity well for four years, but in 1951 membership started to decrease while debt increased. By 1958 there were only seven active members. The house mortgage loomed at $13,000. With the foreclosure of the house mortgage lying ahead, the downfall of the fraternity seemed imminent.

At this time, Professor Everett "Doc" had proceeded to contact several interested alumni. Together they formed Lambda House Inc. Lambda House Inc. took the title to the house and set up plans for the repayment of the mortgage.

In 1958, "Doc" Schadt formed the Alumni Association to instill alumni interest and support of the fraternity. After seven years of hard work, on May 3rd, 1965, all alumni were invited back to the fraternity to participate in the mortgage burning ceremony. In 1967, Alpha Gamma Upsilon purchased the house at 406 West Gale St. as an annex to the main house. The annex was to provide additional housing for the growing brotherhood.

Being one of the only chapters of Alpha Gamma Upsilon left, the brothers of the Lambda Chapter sought affiliation with a new, growing fraternity. After inquiries to many different fraternities, the brothers and alumni agreed upon Sigma Phi Epsilon. The Lambda Chapter of Alpha Gamma Upsilon became a colony of Sigma Phi Epsilon in April 1967. After completing their colonization, which lasted thirteen months, the brothers were initiated and became the Indiana Theta Chapter of Sigma Phi Epsilon on May 4th, 1968.

Since 1968, Indiana Theta has been awarded eight Buchanan Outstanding Chapter Awards. In the spring of 1973, the brothers began a major reconstruction and remodeling of the physical structure of the houses, entailing thousands of man-hours. That summer, both houses were turned over to a construction company for extensive interior renovations to prepare the buildings for occupancy by the brotherhood.

In the fall of 1973, the brotherhood returned two weeks early to finish the houses, but found only half of the major construction work finished. Undaunted, the entire brotherhood lived in Stewart Hall during the fall quarter of 1973. The remodeled house was officially dedicated on May 4th, 1974. In the spring of 1978, Lambda House Inc. purchased the house at 108 South Superior Street. This house became the second annex to the main house.

Summer of 1988 brought a plethora of alumni back for a work session. The 108 was resided, the interiors of the 406 and 108 were repainted, and the roofs were re-shingled.