Thomas Randolph (1523–1590) was an English ambassador serving Elizabeth I of England. Most of his professional life he spent in Scotland at the courts of Mary, Queen of Scots, and her son James VI. While in Scotland, he was embroiled in marriage projects and several upheavals. In 1568-1569 he was sent on a special embassy to Russia, visiting the court of Ivan the Terrible.
Randolph was also a Member of Parliament: for New Romney in 1558, Maidstone 1584, 1586 and 1589, Grantham 1559 and St Ives 1558 and 1572.
Thomas Randolph was born in 1523, the son of Avery Randolph of Badlesmere, Kent. He entered Christ Church, Oxford at the time of its foundation, and graduated B.A. in October 1545, and B.C.L. in 1548. Shortly afterwards he became a public notary; and in 1549 he was made principal of Broadgates Hall (now Pembroke College), Oxford. He continued there until 1553, when the Protestant persecutions under Queen Mary compelled him to resign and retire to France. Sir James Melville refers to Randolph's indebtedness to him "during his banishment in France"; Randolph seems to have mainly resided in Paris, where he was still living as a scholar in April 1557. It was probably during his stay in Paris that he came under the influence of George Buchanan, to whom, in a letter to Peter Young, tutor of James VI, he refers in very eulogistic terms as his 'master'. Among his fellow-students and intimates in Paris was Sir William Kirkcaldy of Grange.