Aa-1 or AA1 may refer to:
- , a United States Navy submarine also known as USS AA-1
- K-5 (missile), an early Soviet air-to-air missile, NATO reporting name AA-1 'Alkali'
- Grumman American AA-1, a light aircraft
- PRR AA1, a Pennsylvania Railroad electric locomotive
- Phoenix Wright: Ace Attorney, a video game
- Acer Aspire One, a netbook computer
- American Airlines Flight 1 (disambiguation), various flights
- Aa1 is the second highest credit rating given by Moody's Investors Service
- Bavarian AA I, a steam locomotive
- 1997 AA1, the alternate name for 8735 Yoshiosakai, an outer main-belt asteroid
- Gardiner's designated symbol for the hieroglyph that represents a sieve or placenta: <span style="font-size:xx-large;">𓐍</span>