John Adam (5 March 1721 - 25 June 1792) was a Scottish architect. Born in Linktown of Abbotshall, now part of Kirkcaldy, Fife, he was the eldest son of architect and entrepreneur William Adam. His younger brothers Robert and James Adam also became architects.

The Adam family moved to Edinburgh in 1728, as William Adam's career as a designer of country houses began to take off. John attended Dalkeith Grammar School, outside the city, although he did not proceed to university as he was already being involved in the family businesses. However, the family home became a hub of the Scottish Enlightenment, with numerous Edinburgh virtuosi visiting.

During the 1740s, William was gradually handing over control to his eldest son. Upon William's death in June 1748, John took over the family businesses, which besides designing and building houses, included interests in quarrying, mining and other industries. John also became laird of Blair Adam, the estate in Kinross-shire which his father had built up. Finally, John inherited his father's position as Master Mason to the Board of Ordnance in North Britain.

John took his younger brother Robert into partnership, and the two profited greatly from the lucrative Board of Ordnance contracts which were had been initiated following the Jacobite Rising of 1745. These included the building of Fort George near Inverness, to the designs of military engineer Colonel Skinner.

The brothers also continued to execute their late father's designs, including the pavilions and interiors of Hopetoun House. Their first major new commission came in 1754 from William Dalrymple, Earl of Dumfries. The new Dumfries House in Ayrshire was probably mostly to the design of Robert Adam, the more talented architect of the two. Robert oversaw the construction of the house until late summer 1754, when he left on his Grand Tour to Italy. Even when abroad, Robert continued to send home designs. John concentrated on the business side of the practice, although he was a competent, if formulaic, architect.

John did win a competition to design a new Royal Exchange in Edinburgh, but he was not appointed as contractor. The successful contractor then appointed another architect, who made changes to the design. However, the building, which now serves as the City Chambers, is still often attributed to John Adam.

On Robert's return to Britain, he established himself in London, where he was joined by the younger brothers James and William. John continued to look after the family's Scottish interests, investing in further quarrying ventures, and the Carron Iron Works. He supplied his London-based brothers with capital from the Blair Adam estate, at least until the collapse of a stock market venture by his friend Andrew Fairholme in 1764 left him out of pocket. Further losses occurred after the failure of Robert's Adelphi building speculation in 1772, and John was forced to mortgage Blair Adam.

John Adam designed other houses in Edinburgh, including Milton House in the Old Town, and Hawkhill, for Lord Alemoor. Among his more significant work was Adam Square, a speculative development of three houses on his own property in the city. The development, although not a true "square", represents one of the first terraces of townhouses in Edinburgh. Construction began in 1761, and despite the financial troubles, Lord President Robert Dundas was able to move in in 1768. Adam himself also lived there until 1772, as well as having a villa at Merchiston. Adam Square was demolished in the 1870s, and the site is now occupied by Adam House, a building of the University of Edinburgh.

Upon his death in 1792, he was succeeded as laird of Blair Adam by his only surviving son, the politician and judge William Adam.

John Adam is an Australian actor, appearing frequently on television.

His credits include: Home and Away, A Country Practice, Water Rats, All Saints, Farscape, Above the Law, Stingers and Always Greener.

John Adam (born in Sydney, New South Wales) is an Australian former rugby league player for the North Sydney Bears in the New South Wales Rugby League competition. His position of choice was in the centres though he could also and often did play on the wing.

Adam showed much promise on the sporting field all through his youth, where he played for and captained the New South Wales under 19's rugby league and cricket sides which forced him to make a decision as to which sport he would continue with past his adolescence. He decided on attempting to forge a career in rugby league and after a brief trial with North Sydney in 1977 he was signed on to a permanent role with the club.

Outside of his sporting exploits Adam was a graduate in law from the University of NSW, skills in which after his retirement still became useful in rugby circles where he became the inaugural president of the players association, which later would become the players union.

John Adam was Viceroy of India in 1823.

John Adam (1779 - 1825) was the British administrator in India, serving as the acting governor-general of the British East India Company in 1823.