I have two chis and a maltese x and they all get along wonderfully. I was very lucky that they took to each other so well. I got Gypsy as a puppy, and jayde at 15 months old. Gypsy was immediately a happier dog, not that she was unhappy before! But it is wonderful to see they get on so well. My older dog coco was not very sociable before i got the chis, she was 5 at the time, and it really brought her out of her shell. So I guess I was very lucky that they were so compatible, but introductions are also important, make sure their first meeting is fun, lots of treats helps! Good luck