I haven't seen this show since the early 90s, and now I'm watching on Prime. I had totally forgotten that Lisa's Yorkie appeared in the actual episodes. I only remembered the dog from the opening. Does the dog disappear at some point?

Yeah he eventually disappeared. He was in a handful of season 1 episodes and a few isolated appearances in 2 and 3. They never gave an explanation. In a later season Oliver says they do not have a dog.

Welcome to the boards. Hope you stick around :wave:

I've always assumed that Oliver just got tired of Lisa's hotcakes and well you know...when you're hungry, LOL JK. Maybe she off with the Petticoat Junction Dog (who's name was "Dog").