Diekstra (born 20 July 1946, Sneek, the Netherlands) is a Dutch psychologist.
He is the developer of many psychological programs for policy and well-being and writes for Dutch regional newspapers and several magazines.
He was also one of the first recipients of the Stengel Award, the world's most prestigious honor in the field of research on suicide.
From 2002 to 2011 Diekstra was head of the research group for Youth and Development at The Hague University of Applied Sciences.
Between 2004 and 2011, he was head of the social science department and professor of psychology at the Roosevelt Academy in Middelburg, the Honors College of the University of Utrecht.