NSA

On All The Tropes, could refer to:

Film

• No Strings Attached
• "National Supers Agency", the organization that keeps files on all knows supers in the universe of The Incredibles

Literature

• New Series Adventures, the Expanded Universe for the post-hiatus Doctor Who continuity

Music

• Neue Schubert-Ausgabe, the collected works of Franz Schubert

• National Sound Archive, the audio collection of the British Library (Wikipedia article)

Real Life

• National Security Advisor, a high-ranking official government position in Canada, India, and the United States of America
• National Security Agency

Not to be confused with NASA.