William Edward Gregory-Leeson^[1] (born 13 October 1943) is an English filmmaker who was one of the founders of the charity War Child, which particularly focuses on help for children in war situations.

In 1993, Leeson and David Wilson produced a documentary film featuring child victims of the war in former Yugoslavia. What they saw so deeply shocked them that they established War Child, which today is a network of independent non-governmental organisations (NGOs) operating across the world to help children affected by war.

In early 1999, Leeson stepped down as CEO as a result of accepting a bribe from the contractors of a musical therapy centre in Sarajevo.^[2] Leeson and the current War Child management and board enjoy a good relationship, with Leeson invited to advise War Child and attend its 15th-anniversary celebrations for the Help CD in 2010.^{[citation needed]}

Today Leeson is one of the founders and directors of GardenAfrica, a charitable organization set up in 2002 to support African families through a range of garden-related initiatives. The project seeks to transform derelict land adjacent to schools, hospitals, and clinics in African communities to help provide food security, health and nutrition, education and training, and sustainable livelihoods.