Diamond Creek is a suburb of Melbourne, Victoria, Australia, 23 km north-east of Melbourne's Central Business District. Its local government area is the Shire of Nillumbik. At the 2016 Census, Diamond Creek had a population of 11,733.
In the postwar years, population increased dramatically in Diamond Creek and its neighbouring areas. The Diamond Valley Shire was created out of the northern part of the Shire of Heidelberg in 1964. Further population growth occurred throughout the 1970s.
The early twentieth century saw a decline in the orchard industry, as orchards in Melbourne's eastern townships such as Doncaster and Nunawading, fell into favour due to better marketing. Diamond Creek remained relatively untouched during the boom in recreational travel that followed the popularity of the motor car.