Yes you can as long as it is not a dedicated circuit.It says in article 210.21(B)
(1) that a single recepticle (not duplex) installed on an individual branch circuit shall have an ampere rating not less than that of the branch circuit.Basically if you are installing a dedicated circuit to a recepticle, that recepticle has to be a single recepticle equal to the branch circuit rating, but if you are installing two or more 15 amp duplex recepticles then they can be on a 20 amp circuit.
I believe if you look at the definitions of a receptacle in references and note "contact device", you will find it permissible to install a (one) 15 amp DUPLEX on a 20 amp circuit.