Depends on where you get it from.
Any responsible breeder will purposely introduce a kitten (of any breed) to household dogs at an early age so that if they get adopted by an owner that has a family dog the kitten will be used to it.
Ragdolls by breed, are EXTREMELY easy going hence the name 'ragdoll' given because when you pick one up he should be like a ragdoll in your arms. They are an extremely docile breed similar to Persians and Himalayan's so they adapt very well to other household pets. However, every cat is an individual so there is no telling exactly how your kitten will react to other pets but odds are your dog may have more of a problem with a kitten than the other way around.
BTW....this is the breed I'm currently looking into for a kitten because my cat (who I've had since I was 9) has basically been sent home from the vet to die and he is my angel! so I'm devastated. The Ragdoll breed closely resembles exactly what my Bunny's personality was like; easy going, sweet, and quite clingy almost like a dog.
