William Bellenden, Lord Bellenden (died 1671), was Treasurer-depute of Scotland.
Bellenden was born before 1606. He was the son of Sir James Bellenden of Broughton, and Margaret Ker. On 10 June 1661 he was created Lord Bellenden, was made treasurer-depute, and was placed on the privy council of Scotland. In 1662 John Maitland, 1st Duke of Lauderdale, on the advice of his brother, managed to secure Bellenden's interest in his struggle with John Middleton, 1st Earl of Middleton and faction over religious policy; and he is from that time one of his most frequent correspondents. He kept Lauderdale informed on the plans of James Sharp, to whom he was hostile.
When the treasurership was taken from John Leslie, 7th Earl of Rothes in 1668 and was put into commission, Bellenden was one of the commissioners. He was then in failing health, and was noted for his overbearing manners at the treasury board meetings, especially when, as was the case, his own accounts as treasurer-depute were called in question, or when any matter of precedence was in dispute.
He died during 1671. His title and fortune he left in 1668 to John Ker, the second son of the Earl of Roxburghe, later John Bellenden, 2nd Lord Bellenden.
This article incorporates text from a publication now in the public domain: "". Dictionary of National Biography. London: Smith, Elder & Co. 1885–1900.