Stephen John Biddulph AM[1] (born 15 August 1953 in Saltburn, England) is an Australian author, activist and psychologist who has written a number of influential best-selling books; and lectures worldwide on parenting, and boys' education.

[2][3] Biddulph's books argue for a more affectionate and connected form of parenting, and the importance of role models in children's lives.

He is one of a group of child development specialists in the UK and elsewhere who argued successfully for the introduction of parental leave in that country, and cautioned on the dangers of institutional daycare for the under twos.

He also campaigned on Australia's mistreatment of refugee parents and children under the Howard government, and led and funded a five-year project to create a permanent national memorial to the SIEV X sinking, on the lakeshore in Canberra.

Steve Biddulph was appointed adjunct professor in the School of Psychology and Counselling, Cairnmillar Institute, Melbourne, in March 2011.