John Frederick Daynes III (1910-1980) was a businessman in Provo and Salt Lake City, Utah.

John Frederick Daynes III was born September 25, 1910 in Salt Lake City, Utah to John Frederick II and Mary Ann Anson Daynes. He spent his early years in Salt Lake City where he lived with his family on 3rd Avenue. In 1919, when Daynes was nine, his mother died of diabetes and heart weakness. His father married Mabel Pearl Anderson in 1920. Daynes served a three year mission for the LDS Church in the Swiss/German mission from 1931-1933 and upon his return he graduated from the North Pacific College of Optometry in Portland, Oregon. While there he met and married Bernice Jeanette Kayser on November 3, 1935. They later had four children: Judith Ann, Maralyn Jeanette, Jacqueline, and John Frederick IV. The couple initially lived in an apartment in Salt Lake City but moved to Provo shortly after Maralyn's birth. There, John was the proprietor of the "Daynes' Optical," "Daynes' Jewelry" and co-proprietor of "Utah Optical Supply" located in Salt Lake City. Daynes and Bernice divorced on April 18, 1962. On September 10, 1962, Daynes married Cora Hatch, with whom he had worked in the optical business. She passed away due to breast cancer on January 18, 1967. Daynes then married Elma Cheney on May 6, 1968.

Daynes passed away on March 27, 1980 in Provo, Utah.