Polka Dot Door was a children's television series produced and broadcast by TVOntario from 1971 until 1993.

The show, which aired daily, was set in a large playhouse. Each episode had two human hosts, always one man and one woman, although there were many different human hosts over the course of the series. The hosts would lead children in songs and stories, and interact with stuffed animal characters Humpty, Dumpty, Marigold and Bear.

Hosts of Polka Dot Door included Dennis Simpson, Gloria Reuben, Tonya Lee Williams and Cindy Cook.

Polkaroo

Each day's episode had a theme. On "Imagination Day", the character Polkaroo would appear. The actor playing Polkaroo donned a tall, green plush costume that resembled a kangaroo. In its mended, yellow and multi-coloured polka-dot muumuu, the creature never spoke other than the occasional exclamation of its own name. Polkaroo appeared only to one host while the other was away, performing a pantomime whose meaning was guessed by the audience. The missing host would return upon Polkaroo's departure, habitually exclaiming, "Aw, I missed him again."

Because of the irony laden in this sentence, Polkaroo has become something of a cultural icon to the generation raised on Polka Dot Door, and the catchphrase "Aw, I missed him again" may often be employed for humorous effect.

In the late 1990s, TVOntario capitalized on the success of Polkaroo by placing him and the other animal characters in a new series, Polka Dot Shorts.