The Masked Rider is a 1919 American silent Western film serial directed by Aubrey M. Kennedy. Scenes were filmed in Mission San Jose in San Antonio, Castroville and Bandera, Texas, and in Coahuíla, Mexico. The serial was long thought to be lost in entirety.

In 2003, however, The Serial Squadron acquired 22 color-toned 35mm nitrate reels of a surviving print of the serial which had been recovered from the estate of a former Pennsylvania theatrical projectionist who had condensed the serial many years ago, removing opening titles and leaving out first reels of several later chapters which contained more dialogue than action. Two reels of Chapter 1, the conclusion of Chapter 3 and most of Chapter 11 are missing. Chapter One and the conclusion of Chapter 3 were recreated by The Serial Squadron using local actors. The condensed version of the serial, restored by Eric Stedman and presented in 9 chapters, with opening and closing titles, is available on dvd.

The Masked Rider is considered to be the first film serial about a major masked mystery-Western character who is referred to by his name in the title, and can thus be considered a prototype "Lone Ranger" of sorts. The 15-episode serial is also significant for being the earliest surviving film appearance of actor Boris Karloff. His appearance in the film is disputed by some but most sources, including the 1970s Karloff biography by Peter Underwood, list Karloff as being in the film. Karloff himself provided information for the Underwood book in which the serial is listed in his filmography as "The Masked Raider" which is how he remembered it. Karloff had been hired to play the villainous Rodriguez (who, after causing a great deal of trouble, is shot down by the Masked Rider in the first chapter) and multiple other roles in the rest of the serial, but did not arrive in San Antonio in time to shoot Chapter 1 so his part was recast and after he did arrive at the Shamrock studio he was given pay for a day's work in chapter 2. The Masked Rider's all-black costume was adapted for use by Zorro in the Douglas Fairbanks feature which was released later in 1919. Up to that point Zorro had been portrayed in magazine illustrations as wearing a sombrero and colorful Mexican attire.