Delta Sigma Lambda (ΔΣΛ) was a social fraternity founded on September 9, 1921, formed entirely of members of the Order of DeMolay.

By December 25, the consolidation was finalized, taking the name and founding date from Delta Sigma Lambda, the oldest group.

The reduction of student enrollment and tightened budgets during the depths of the Great Depression hit all fraternities hard.

In September 1933, a smaller, regional fraternity named Theta Alpha, founded on February 22, 1909, merged into Delta Sigma Lambda.

Scattered alumni and some of Delta Sigma Lambda's chapters either withdrew to join other national fraternities or went local.

Half of the surviving chapters joined Theta Chi, three others either immediately or with a local stop, went to other national fraternities.