Diddillibah is a rural/residential suburb immediately west of Maroochydore, where the Eudlo and Petrie Creeks enter the Maroochy River. The suburb's northern boundary follows the Petrie Creek upstream for about 2 km and then the Paynter Creek for about 6 km to Woombye.
It is thought that Diddillibah was named after an Aboriginal expression indicating a carpet snake; it was also spelt 'Didillibah' until 1994.
The first farm selection occurred in the late 1860s along the Petrie Creek. Selections were taken up more quickly in the 1880s as sugar mills and the railway seemed more certain to be built and successfully operated. A primary school was opened in 1885, continuing until 1962. In addition to cane-growing, timber was cut and floated downstream for milling.
By the early twentieth century the post office directory recorded nine sugar planters, four other farmers and a sawmill at Diddillibah. By the mid-1920s fruit growing outnumbered the six cane growers by three to one, and a couple of teamsters still brought out timber. There were also five dairy farmers. In the early postwar years the situation was little changed, although there were slightly more cane growers and fewer fruit growers.
About one-third of the way along the road to Woombye there is the Diddillibah cemetery (1896) behind the former school which is now a community hall. The 'business end' of Diddillibah is at the river mouths, where there is the Maroochy River Waterfront Resort (1990) and other holiday accommodation. They adjoin the Eudlo Creek Environmental Park.
Council rejected an application for a large unit development on the flood plain at Diddillibah in 2009.
Diddillibah's census populations have been: