P3A
P3A may refer to:

 P3a, a component of brain activity 
 Public-Private Partnership Authority (Pakistan), an organization by the Government of Pakistan
 Plasma membrane -ATPase (P3A ATPase), an enzyme
 Bowin P3a, a racing car
 P3A, a Canadian postcode assigned to Greater Sudbury
 P3A (Paphos Third Age), an affiliate of University of the Third Age