Blaine Willenborg (born January 4, 1960) is a former professional tennis player from the United States. Willenborg enjoyed most of his tennis success while playing doubles. During his career he won 7 doubles titles and finished runner-up an additional 9 times. He achieved a career-high doubles ranking of World No. 13 in 1988. His career high singles ranking was world No. 50, which he reached on September 9, 1984.