This is a question that many parents ask themselves when they first get a family pet. While there's no set answer, generally speaking, kids should be at least four years old before attempting to walk a dog by themselves.
Of course, every child is different and some may be ready to start walking the dog solo earlier than four years old while others may not be ready until they're older.
If you're unsure of whether or not your child is ready to take on this responsibility, it's always best to err on the side of caution and wait a bit longer.
Small breeds are easier for small children to walk, while large breeds are impossible for a child to walk until they are teenagers.