Donald Richard Spencer (born 22 March 1937) is an Australian singer-songwriter, musician, and former children's television presenter. He had a long tenure as a host on Play School on both the Australian version (1968–99) and the United Kingdom version (1972–88), one of only two presenters to work on both versions.

In March 1963, his first single, "Fireball" – the theme tune to a UK TV science fiction series Fireball XL5 – reached No.32 on the UK Singles Chart. In 2002, Spencer established the Australian Children's Music Foundation. On Australia Day (26 January) 2007, he was awarded a Medal of the Order of Australia (OAM) with the citation "for service to children's music and television as a songwriter and performer, and through the establishment of the Australian Children's Music Foundation". Spencer married Julie Horsfall, they have two children: Dean, a musician; and Danielle, an actress and singer, who was married to actor Russell Crowe between 2003 and 2018. In 2022, he celebrated his 60th year in the performing industry.