Where can I leave my luggage in Granada?

Left-luggage lockers in Granada:

Granada City Center Luggage Storage:

Very convenient place near the cathedral. Leave your bags for hours or days.
There are discounts for advanced booking
Click here

There is a left luggage place in Plaza Nueva

Bus station
There are lockers at Granada bus station.
Estacion de autobuses.
Estacion de autobuses

To get to the bus station get on a 33 bus from the Gran Via and Avenida de la ConstituciĆ³n

Also there are lockers at the Alhambra. It is free if you have bought a ticket. The luggage office is located outside and downstairs from the main ticket office..

There is some more information here

We Locker Granada
Just behind burger king in Puerta Real
Calle Campo Verde, 2, 18001 Granada
622 61 00 06
This website appears to be down maybe they don't exist anymore. 

Lock and Be Free 
Address: Salamanca, 13
This is a side street between Plaza del Carmen abd Bib Rambla.
The website is not very up to date with info about the Granada office.