Hillsbus was an Australian bus company that operated services in the Hills District of Sydney.

Founded in 2004 when National Express merged its Glenorie Bus Company and Westbus (Hills District operations only) subsidiaries, it was later part of ComfortDelGro Australia.

In 1996, Westbus established a separate Hillsbus brand to run express services from the Hills District to the Sydney CBD and North Sydney, initially via the Anzac Bridge and from 1997 via the M2 Hills Motorway.

[6][9] In December 2004, all Westbus routes operating out of Northmead and Seven Hills depots, as well as the rest of Glenorie Bus Company, were rebranded Hillsbus.

[14] When the Parramatta - Rouse Hill section of the North-West T-way opened on 10 March 2007, routes 730 (renumbered T63) and 735 (renumbered 616, now 616X) were transferred from Busways to Hillsbus with route 718 transferred from Hillsbus to Busways.

[15] On 30 June 2014, the Opal card was rolled out on all of Hillsbus' NightRide and Region 4 routes (including school services).

[20][21] From 2005 until its replacement by CDC NSW in 2023, Hillsbus' services had formed Sydney Bus Region 4.