David Brian Nelson (born June 12, 1943) is an American musician, singer, and songwriter. He is perhaps best known as a co-founder and longtime member of the New Riders of the Purple Sage.

Nelson started his musical career playing folk and bluegrass music, most notably as a member of The Wildwood Boys with Jerry Garcia. Shortly after his friend and former bandmate began to play rock music with The Warlocks (subsequently renamed the Grateful Dead), Nelson joined the similarly inclined New Delhi River Band. Although they lacked the managerial acumen and cultural cachet of the Grateful Dead and elected to remain in East Palo Alto, California unlike the former group, who soon relocated to the Haight-Ashbury district of San Francisco, the New Delhi River Band were considered to be the house band of The Barn (one of the region’s few viable concert venues outside of San Francisco) in Scotts Valley, California by late 1966. The group continued to enjoy a cult following in Santa Clara and Santa Cruz Counties through the Summer of Love until their dissolution in early 1968.