Robert Gayler (May 6, 1873 – February 15, 1954) was an accomplished American pianist, organist, celesta player, arranger, and music educator. Born in New York, Gayler's musical journey began early; by the age of fifteen, he was already serving as the organist for one of Brooklyn's largest churches. He pursued formal studies in piano under notable teachers such as Xaver Scharwenka and Almon Kincaid Virgil, as well as organ instruction from Robert J. Winterbottom.

From 1903 to 1908, Gayler worked as an operatic coach at The Metropolitan Opera House, where he developed a distinguished career as a piano accompanist, collaborating with prominent opera and concert singers. He was also recognized as one of the leading players of the celesta—a hammer-struck idiophone with a keyboard size similar to that of an upright piano, invented in the 1860s. Throughout his career, Gayler held various positions as a conductor and musical director for churches and ensembles in Brooklyn, New Jersey, Long Island, and Branford, Connecticut.

In late 1916, Gayler joined Edison Laboratories, where he played a significant role in the New York Recording Studio until 1937. His contributions included a notable appearance in the November issue of Edison Phonograph Monthly, featuring his celesta rendition of "Christmas Eve," which was released on a Blue Amberol 4-minute cylinder. Over the years, he recorded on various formats, including the short-lived Royal Purple Amberol series and multiple generations of vertical-cut Diamond Discs.

In 1919, Gayler participated in a landmark series of recordings with composer Sergei Rachmaninoff, performing original works on a concert grand piano manufactured by S. D. Lauter & Co. This piano was one of the few models produced by the Newark-based company founded by German-American piano maker Solomon David Lauter in 1862. Thomas Edison, the founder of the label, was largely deaf due to a combination of scarlet fever and head trauma in his youth, which limited his musical appreciation. Despite his lack of musical sophistication, Edison personally oversaw the catalog and approved each artist. His notoriously poor A&R choices included dismissing popular songs as "miserable dance and ragtime selections" and viewing jazz as "for the nuts." He initially regarded Rachmaninoff's exceptional technique as merely that of a "pounder," leading Gayler and the label staff to advocate for Rachmaninoff's signing, which ultimately resulted in a ten-record deal.

In his later years, Gayler served as a Professor of Organ and Dean of the School of Music at Florida Southern College. He was married to soprano singer Marie Fahnestock Stoddart (1878–1939). Robert Gayler passed away on February 15, 1954, in Interlachen, Florida, leaving behind a rich legacy in American music.