ISAS may refer to:

• International School for Advanced Studies, a post-graduate teaching and research institute in Trieste, Italy
• Institute of Space and Astronautical Science, a Japanese research institute which is former independent space agency, now a part of Japan Aerospace Exploration Agency (JAXA).
• Independent Schools Association of the Southwest, an association of 89 independent schools located in Arizona, Kansas, Louisiana, New Mexico, Oklahoma, and Texas.
• Ictal-Interictal SPECT Analysis by SPM, a method of localizing seizures
• Idaho Science and Aerospace Scholars, an Idaho based program focused on Aeronautics. Only for Idaho residents who are Juniors in High School.

• The Limited Series (1998 album)
• The Limited Series (2005 album)
• The Limits of Control
• The Limits Of The Imagination
• The Limo
• The Limo (disambiguation)
• The Limo (How I Met Your Mother)
• The Limo (Seinfeld)
• The Limo (Yes, Dear episode)
• The Lincoln Center
• The Lincoln Conspiracy
• The Lincoln Conspiracy (book)
• The Lincoln Conspiracy (film)
• The Lincoln Group
• The Lincoln Imp
• The Lincoln Lawyer
• The Lincoln Near-Earth Asteroid Research
• The Lincolns
• The Lincolnshire Flag
• The Lincolnshire Poacher
• The Lincolnshire Regiment
• The Linconshire Poacher
• The Lindbergh baby
• The Lindsay Affair
• The Linear Guild