Guy Williams Prof. John Robinson Actor June Lockhart Maureen Robinson Actor Mark Goddard Don West Actor Marta Kristen Judy Robinson Actor Bill Mumy Will Robinson Actor Angela Cartwright Penny Robinson Actor Jonathan Harris Dr. Zachary Smith Actor Dick Tufeld Robot Actor Dennis Patrick Keema Guest Star Ron Gans Voice of Frog Alien Guest Star Bill Troy Handsome Alien Guest Star Irwin Allen Producer Barney Slater Writer Don Richardson Director