In the 2011 census, Slacks Creek recorded a population of 10,435 people, 50.7% female and 49.3% male. The median age of the Slacks Creek population was 32 years, 5 years below the national median of 37. 62.9% of people living in Slacks Creek were born in Australia. The other top responses for country of birth were New Zealand 9.9%, England 3.3%, Samoa 1.5%, Philippines 0.9%, Fiji 0.8%. 75.9% of people spoke only English at home; the next most common languages were 3% Samoan, 1% Hindi, 0.6% Khmer, 0.6% Arabic, 0.6% Romanian.