Alpha Sigma Lambda (ΑΣΛ) is an American honor society for non-traditional students in colleges and universities. It was established at Northwestern University in 1946 and has chartered more than 230 chapters. It is a member of the Association of College Honor Societies.

Dr. Rollin Posey established Alpha Sigma Lambda at Northwestern University in 1942, to recognize the accomplishments of those returning to academic pursuits after the close of World War II. Its purpose, he wrote, "is to bind together in one Society the excellent students within the University College to provide a stimulus for and recognition of their worthy efforts." The honor society supports nontraditional students who are trying to obtain their first associate or baccalaureate degree.

Alpha Sigma Lambda became a member of the Association of College Honor Societies in 2011. In 2011, it had chartered 325 chapters.

As of 2024, Alpha Sigma Lambda has 233 active chapters. Its headquarters are at Eastern Illinois University in Charleston, Illinois.

The Greek letters of the society's name were selected to represent Alpha for First, Sigma for Scholarship, and Lambda for Leadership. The motto of Alpha Sigma Lambda is "First in Scholarship and Leadership".

The society's crest displays the Greek letters ΑΣΛ and its symbols, the book, the lamp, and the torch. The book represents a love of knowledge, the lamp symbolizes wisdom, and the torch stands for life.

Its colors are burgundy and gold. Burgundy represents action, power, and the confidence to follow your dreams. Gold symbolizes good health, optimism, prosperity, success, and wisdom. Its publication is the Midnight Oil Newsletter.

Annually, Alpha Sigma Lambda awards its Continuing Education and Lifelong Learning Scholarships.