The Heart of Midlothian /mɪdˈloʊðiːən/ is a heart-shaped mosaic, formed in coloured granite setts, built into the pavement near the West Door of St Giles High Kirk in the High Street section of the Royal Mile in Edinburgh. It is situated close to Parliament House, which formerly housed the Parliament of Scotland and is now the home of the Court of Session.
Together with brass markers bearing building dates, it records the position of the 15th-century Old Tolbooth, demolished in 1817, which was the administrative centre of the town, a prison, and one of several sites of public execution. The building features in Sir Walter Scott's novel The Heart of Midlothian, published in 1818.
The mosaic is named after the historic county of Midlothian of which Edinburgh is the county town. This is not to be confused with the council area of the same name which covers a smaller area and does not include the capital. The crest of the Edinburgh football team Heart of Midlothian is based upon this Heart.