CA2
CA2, CA-2 or CA II may refer to:
- Carbonic anhydrase II, a human gene
 - United States Court of Appeals for the Second Circuit
 - California's 2nd congressional district
 - Hummel CA-2, an ultralight aircraft
 - California State Route 2
 - Ca II, a singly-ionized calcium that produces the calcium triplet lines in the spectrum of many stars
 - Cornu Ammonis 2, a region of the hippocampus
 
See also
- Ca2+, the calcium cation