The actor, who played Richard 'Boner' Stabone in the 1980s sitcom, was discovered dead in a Vancouver park last week after he was reported missing by his family.
Speaking to ET Online, Thicke (Dr Jason Seaver) said: "Andrew's light shone brightly on the Growing Pains set.
"His skill and humour and friendship were important elements in our extended family. May his own family now find comfort in their memories of the good times with this very special young man."
Fellow Growing Pains stars Kirk Cameron and Tracey Gold have also expressed their condolences following Koenig's death.
> Andrew Koenig "happy" in final role