Sigma Lambda Alpha (ΣΛΑ) is a North American scholastic honor society that recognizes academic achievement among students in the field of landscape architecture.

[1] The CELA executive board established Sigma Lambda Alpha was founded at University of Minnesota in Minneapolis on September 24, 1977.

[2][3][1] Wiliam H. Snyder of the University of Idaho was appointed the first executive secretary of Sigma Lambda Alpha and was charged with convening a task force to form the society.

[4][1] The purpose of Sigma Lambda Alpha is "to encourage, recognize, and reward academic excellence in preparation for the profession of landscape architecture".

[5] Sigma Lambda Alpha was admitted to the Association of College Honor Societies in 1983 and achieved full membership in 1986.