The move was introduced this week at Wilko, on Nottingham Street, and at 247 of its other outlets in the UK.
It follows a successful pilot at two Wilko locations.
Furry friends, on their leads if applicable, will be able to browse all areas of the participating stores, except for the food aisles.
New signage is provided to inform customers that they no longer need to leave their pet outside the store.
Only Wilko stores with on-street entrances are allowing dogs.