While Jim Coates (Fess Parker) is off on a cattle drive, his wife, Katie (Dorothy McGuire), and sons, Travis (Tommy Kirk) and Arliss (Kevin Corcoran), are left behind on their Texas ranch. When a runaway dog named Old Yeller causes damage in one of their fields, Travis tries to drive him away. However, Travis and Katie both warm to Old Yeller when he saves Arliss from a bear attack. As Travis and the brave and faithful dog grow closer, concern grows about an outbreak of rabies.