|Friends||T-Bone, Cleo, Mac|
|Families||Emily Elizabeth Howard (owner)|
|First appearance||My Best Friend|
|Voiced by|| Brent Titcomb (1988 series) John Ritter (original series, "Clifford's Really Big Movie")|
Lara Jill Miller ("Clifford's Puppy Days"<be>Frank Welker (PBS Kids "Ready to Learn" bumpers)
Clifford, also known as Clifford the Big Red Dog is the big red dog of Emily Elizabeth's and also the main protagonist of the show. He was voiced by Brent Titcomb in the 1988 series, and the late John Ritter in the PBS series that aired from 2000-2003. Clifford is the main character who's size is caused by the amount of love Emily Elizabeth gave him.
Clifford is a helpful, outgoing and a friendly dog. He will always help his buddies in their times of need and give them amazing advice. However, he can also can be gullible and naive and sometimes believes everything he is told.
Clifford is a very big red dog, which sometimes he gets into trouble because of his size or is tempted into trouble by his friends and those he meets. His size, like giants in medieval legends, is inconsistent—he is often shown as being about 25' tall from paws to head, but can appear far larger. Emily Elizabeth gave him a huge amount of love, which caused his big size.
- Although John Ritter died in 2003, his voice can be heard as Clifford as late as 2004 because "Clifford's Really Big Movie" was released posthumously.
- Clifford was given a prequel series "Clifford's Puppy Days" and it takes place before the Howard's move to Birdwell Island. In this series Clifford is played by Lara Jill Miller.
- The reason Clifford grew to his current size was due to being dropped into the cooling vat of a nuclear power plant. He later came out bigger and returned to Emily Elizabeth's home.