Jeff Lumby is a Canadian actor and voice actor. He is a member of the Lumby family, who created and produced the 1980s Canadian children's television series, Size Small, where he appeared as "Tex". In recent years, Jeff is better-known as "Winston Rothschild, III", the septic tank and sewer technician character on The Red Green Show.

Jeff also did some voice work for the English dub adaptation of the Sailor Moon anime series; his sister, Lisa Lumby-Richards (who appeared on Size Small as "Grandma Gussie"), was a scriptwriter for the adaptation.

For eight years, he was a radio personality on Hamilton, Ontario station CJXY-FM, the rock station that was then Y95.3. He subsequently co-hosted the morning show on Toronto country radio station CISS-FM prior to its 1999 flip to contemporary hit radio. In January 2007, he returned to radio as lead morning host on Cambridge, Ontario radio station CJDV-FM, 107.5 Dave FM.