Luddenham is a suburb of Sydney, in the state of New South Wales, Australia 42 kilometres west of the Sydney central business district, in the local government areas of the City of Penrith and City of Liverpool. It is part of the Greater Western Sydney region.

Luddenham takes its name from a property which was situated between South Creek and the Nepean River that was owned by John Blaxland, who received a grant of 6,710 acres (27.2 km) on 30 November 1813. His elder brother was the more famous Gregory Blaxland and Luddenham was the name of their family property in Kent, England.

The first Luddenham Post Office opened on 1 January 1857 and was renamed Bringelly in 1863. The current office opened on 1 March 1872.

In the 2021 census, there were 1,927 people in Luddenham. 80.2% of people were born in Australia; the next most common birthplaces included Italy 2.1%, Malta 1.5%, England 1.2%, Lebanon 1.1%, and Fiji 1.0%. 78.4% of people only spoke English at home; the next most common languages spoken at home included Arabic 4.5%, Italian 2.7%, Maltese 1.7%, Croatian 1.6%, and Mandarin 1.3%. The most common responses for religion included Catholic 49.0%, No Religion 18.7%, Anglican 1.3%, and Eastern Orthodox 3.9%; a further 3.6% of respondents for this area elected not to disclose their religious status.

Luddenham has 1 bus service, route 789 between Luddenham & Penrith, operating only twice per weekday, once around 7:30am and once around 4:14pm.

In June 2020, a Metro station at Luddenham on the Western Sydney Airport line due to be completed in 2026, was confirmed.

33°52′51″S 150°42′53″E / 33.88083°S 150.71472°E / -33.88083; 150.71472