The 2012 presidential campaign of Mitt Romney was his second bid for the Republican nomination, following an unsuccessful 2008 primary run, and culminated in an unsuccessful general election bid against incumbent President Barack Obama. Officially launched on June 2, 2011, in Stratham, New Hampshire, the campaign leveraged Romney's existing political infrastructure from his prior efforts. Post-2008, Romney strategically saved funds from his political action committee to cover salaries and build toward a potential billion-dollar operation, while continuing to fundraise and speak for fellow Republicans. The campaign emphasized Romney's business background and gubernatorial experience, positioning him as a turnaround leader amid economic challenges.

Romney secured the Republican nomination at the 2012 Republican National Convention in Tampa, Florida, selecting Wisconsin Congressman Paul Ryan as his running mate. The campaign faced a prolonged primary season due to a proportional delegate allocation system, which extended contests against rivals like Rick Santorum and Newt Gingrich, fracturing party unity and straining resources. Key moments included debates where Romney gained ground, particularly in the first presidential debate on October 3, 2012, and internal polling that overestimated chances in swing states like Ohio, Pennsylvania, and Florida, leading to overconfidence—no concession speech was prepared. Despite raising substantial funds and outperforming some past Republican nominees in electoral votes, the campaign ended in defeat on November 6, 2012, with Romney conceding after Obama's re-election.

The effort was marked by strategic missteps, such as messaging challenges during the primaries and perceptions of Romney as overly moderate or evasive on issues, as highlighted by campaign insiders and analysts. Post-election analyses pointed to foul-ups like the 'Etch-a-Sketch' comment suggesting a post-primary pivot, which alienated the base, and underestimation of Democratic turnout. The campaign's operations were supported by experienced advisors, including foreign policy experts like Alex Wong, and it influenced subsequent Republican strategies, with many staffers later endorsing other candidates.