Big Aa (disambiguation)
Big Aa is the name of this river:
- a tributary of the Ems in Lower Saxony (Germany), see Große Aa
- a tributary of the Aabach in North Rhine-Westphalia (Germany), see Große Aa (Aabach)
- the nickname of the middle course of a tributary of the Afte in North Rhine-Westphalia (Germany), see Aabach
- a source river of the Aa of Weerijs in the province of Antwerp (Belgium), see Große Aa (Belgium)