Bill Mumy credited as playing...
Will Robinson
- Dr. Zachary Smith: When I was a child I, too, thought like a child, but when I became a man, I had to think like a man.
- Will Robinson: I don't think it matters WHAT age you are: if you're dishonest you're dishonest, and that's all there is to it.
- Will Robinson: How do you like it?
- Penny Robinson: Before I answer, you better tell me what it is.
- Will Robinson: Didn't you ever read Tom Sawyer or Huck Finn? It's a slingshot. Back in the eighteen and nineteenth century almost every boy made one of these.
- Penny Robinson: What for?
- Will Robinson: To carry with his penknife and marbles, I guess.
- The Keeper: Sorry to startle you, children. I've been around animals so long I've begun to move as quietly as they do.
- Will Robinson: We were concentrating hard on our work or we would have heard you.
- The Keeper: I'm sure you would have. The young have very sharp ears.
- Will Robinson: Are you out hunting for animals, Mr. Keeper?
- The Keeper: In a manner of speaking, yes.
- The Keeper: I see you've changed your minds about leaving.
- Will Robinson: [mesmerized] We're sorry, sir. We really want to stay with you.
- Penny Robinson: [mesmerized] For always, Mr. Keeper. Always.
- The Keeper: And so you shall, for always.