Susan Margaret Pennicuik (/ˈpɛniːkuː/ PEN-ee-koo; born 17 April 1957) is an Australian former politician who served as a Greens member of the Victorian Legislative Council from 2006 to 2018. From April 2022 to November 2024, Pennicuik served as a councillor on the City of Glen Eira.

Pennicuik studied Arts at Monash University and later Applied Science, majoring in Physical Education, at the former Footscray Institute of Technology. Afterwards, Pennicuik worked as a fitness instructor.

She then obtained a Diploma of Education from the University of Western Australia, afterwards working as a secondary English and Physical Education teacher.

She then went on to work as an environment officer for the Australian Manufacturing Workers Union, later obtaining a Masters in Environmental Science from Monash University.

She then worked a coordinator for the Occupational Health and Safety Unit of the ACTU from 1997 to 2004, which conducted research and produced OHS information for unions. She worked on national OHS standards and led campaigns on a range of issues including stress and bullying at work, safer working hours and banning asbestos.

Pennicuik then worked for the Australian Drug Foundation from 2004 to 2006 developing resources on alcohol and work. At the same time, she was party convener of the Victorian Greens.

Pennicuik was a candidate for the 1998 Australian Constitutional Convention on the Greens' ticket, listed as 'Australian Greens – For A Republic'.

Pennicuik stood for the former Ormond Ward on Port Phillip City Council in 2004, gaining 34% of the primary votes.