Sir Samuel Thomas Rosbotham (26 June 1864 – 12 March 1950), known as 'Sam Tom', was a British farmer and politician.
Born to Samuel and Mary (née Heathcote) in 1864, he carried on his fathers occupation as a farmer at Holly and Stanley farms in Bickerstaffe, before marrying Jane Heyes in 1887, producing seven children. He was elected to Lancashire County Council in 1895, later becoming a county alderman. In 1909 he became chairman of the Lancashire Farmers Association, a post he held for twenty years.
During The First World War he was the chairman of the Ormskirk War Agricultural Committee, working to make short-term credit available for the small farmers. Following the war he was appointed to the Agricultural Wages Board as an employers' representative.
In October 1922 Rosbotham announced his candidacy as an Independent Conservative candidate for his local constituency of Ormskirk at the upcoming general election. In the event he did not contest the election. By the time of the 1924 general election Rosbotham had changed his allegiance to the Labour Party, campaigning against the sitting Conservative MP, Francis Blundell. Following a bitter contest Blundell brought an action for slander against Rosbotham for making "false statements of fact in relation to the plaintiff's character and conduct for the purpose of affecting his return to parliament".
At the next general election in 1929 Rosbotham stood as the Labour candidate against Blundell at Ormskirk, and was elected to the Commons. His victory was thought to be partly due to a change in the nature of the electorate, due to the building of a number of large housing estates by Liverpool City Council in the area.