Bayside Council is a local government area in Sydney, New South Wales, Australia. It is located around part of Botany Bay, 7 kilometres (4.3 mi) to 12 kilometres (7.5 mi) south of the Sydney CBD. It includes 29 suburbs in Sydney's South. It comprises an area of 50 square kilometres (19 sq mi) and in 2023 had an estimated population of 182,987. The council was formed on 9 September 2016 from the merger of the City of Botany Bay and the City of Rockdale.

The council's mayor is Ed McDougall, of the Australian Labor Party, elected by the council on 9 October 2024.

Suburbs in the Bayside Council area are:

Bayside Council also manages and maintains the following localities:

The City of Rockdale was originally proclaimed as the "Municipal District of West Botany" on 13 January 1871. From 1872, Council met in the first Council Chambers, a small purpose-built stone building on the western side of Rocky Point Road, Arncliffe. It continued in use until 11 December 1888, when a new Town Hall was opened on the corner of Rocky Point Road and Bryant Street, Rockdale. By the time the neighbouring Boroughs of Botany and North Botany (Mascot from 1911) were proclaimed on 29 March 1888, it was clear that a name change was desirable. On 17 May 1888 the Parliament of New South Wales passed the Rockdale Municipality Naming Act (No.33, 1888), and West Botany became the "Municipal District of Rockdale". The 1887 Town Hall was replaced by the current Rockdale Town Hall in 1940, and was designed by Rockdale architect Douglas Gardiner. Under the Local Government (Areas) Act 1948, the Municipality of Bexley, which was located immediately to the West and had separated from Hurstville in 1900, became the First Ward of Rockdale Municipality. Rockdale was declared a city in 1995 as the "City of Rockdale".

The City of Botany Bay was first proclaimed on 29 March 1888 as the "Borough of Botany", and met from 1899 to 2016 in the Botany Town Hall. The northern section of the City of Botany Bay was first incorporated as the "Borough of North Botany" on 29 March 1888. From 28 December 1906, following the passing of the Local Government Act, 1906, the councils were renamed as the "Municipality of North Botany" and the "Municipality of Botany". The Municipality of North Botany was renamed as the "Municipality of Mascot" on 31 October 1911. Under the Local Government (Areas) Act 1948, the Municipality of Mascot was amalgamated into Botany, within a reconstituted Municipality of Botany. Botany remained a municipality until 11 May 1996, when it was proclaimed the "City of Botany Bay".

A 2015 review of local government boundaries by the NSW Government Independent Pricing and Regulatory Tribunal recommended that the City of Botany Bay amalgamate with the City of Rockdale to form a new council with an area of 50 square kilometres (19 sq mi) and support a population of approximately 153,000.

There was significant community opposition to the merger from within both communities. In Botany Bay, residents were given the chance to have their say in a community poll which was held on 27 February 2016. Ultimately 97.8 per cent of Botany Bay residents voted 'no' when asked the question 'Do you agree that the City of Botany Bay should merge with Rockdale City Council?'. Rockdale City Council indicated their preference to merge with the City of Kogarah and the City of Hurstville, forming a single "St George Council". Botany Bay also attempted to seek a compromise by proposing to merge with the City of Randwick and parts of the City of Sydney.