The SeaCity Museum is a museum in Southampton, England, which opened on 10 April 2012 to mark the centenary of RMS Titanic's departure from the city. It is housed within a part of the Grade II* listed civic centre building which previously housed the magistrates' court and police station. The museum contains two permanent exhibitions, one dedicated to Southampton's connection with RMS Titanic, and the other to the city's role as gateway to the world. A third space for temporary exhibitions is housed in a purpose-built pavilion extension to the civic centre. Further phases of development may yet add to the exhibition space.

The museum was designed by Wilkinson Eyre with Kier Southern serving as the main contractor. The budget for the museum was £15M, approximately £5M of which came from the Heritage Lottery Fund, with Southampton City Council and Southampton Cultural Development Trust providing the remainder. The council had planned on selling works from their municipal art collection to fund the museum, but backed down after encountering significant opposition from both within and outside the city.

Plans for a heritage centre in Southampton began to emerge in 2002, with the city council's formation of the Heritage Working Group to explore options and to outline the way forward for such a scheme. In 2004, the following locations were shortlisted as potential sites for the then named "Story of Southampton" heritage centre –

All of the shortlisted sites were deemed too costly and unworkable. Following these developments, in 2006 Southampton Police announced their intention to vacate their civic centre headquarters due to a lack of space. With the magistrates' court having left the building in 2001, this would leave an entire block of the civic centre vacant. And so the civic centre became a candidate to host the heritage centre, and by 2007 was considered the front runner.

Plans were unveiled for the civic centre heritage centre in 2008. The original plans included a 3-storey extension to the building, and a water feature running from nearby Watts Park, both of which were scrapped to reduce the cost by £10M to £28M. The project was split into two phases. The focus of phase one was to be Southampton's Titanic connection, and the Sea City name was attached. Phase one had a budget of £15M and a completion date due in 2012.

Southampton City Council sought Heritage Lottery Funding towards the museum; it was awarded £0.5M in 2009 for the development phase, and a further £4.6M in 2010 for the construction.

To raise the rest of the £15M, in 2009, Southampton City Council proposed selling off works from their municipal art collection. The council selected two works to be sold, an oil painting by Alfred Munnings, After the Race (1937), and one of two bronzes by Auguste Rodin, either Eve (1880) or Crouching Woman (1882). The council believed that these works were not core to the gallery's focus on British modern and contemporary 20th and 21st century art. Due to space constraints at Southampton City Art Gallery, only 200 of the 3,500 works in the collection can ever be displayed there at one time; the council believed that the sale of the two works would allow space to be created in the new museum for the display of 100 further works from the collection. It was hoped that the sale would generate £5M towards the museum.

The proposed sale of the artwork had backing from the local paper, the Daily Echo, which had campaigned for three years for the deaccessioning of pieces from the "overflowing" municipal collection. There were voices of dissent from within the city however, in spite of Alec Samuels, the then Conservative council leader's assertion that, "If we don't sell some paintings we don't get a heritage centre." Councillors from opposition Liberal Democrat and Labour camps described the proposed sale as a "betrayal of public trust" which would damage the reputation of the city's museum. Alan Whitehead, MP for neighbouring Southampton Test described the proposed sale as an "outstandingly bad idea", which would discourage future donations and bequests to the city and destroy the national standing of its gallery. Labour politicians proposed borrowing funds as an alternative to the proposed sale, but the ruling Conservative faction dismissed this plan, arguing that it would lead to either cuts in front-line services, or increases in council tax, to cover interest and repayments.