William Bowes of Streatlam, (died 1611), was an English ambassador to Scotland, Deputy Warden of the West March, Treasurer of Berwick-upon-Tweed, and Member of Parliament for Westmorland.
William was the eldest son of George Bowes of Streatlam and Dorothy Mallory and succeeded to his father's encumbered estates in 1580. He was elected Member of Parliament for Westmorland in 1593
Bowes represented Elizabeth I at the court of James VI of Scotland. His uncle, Robert Bowes, had earlier held the position.
In June 1597 William was sent to Scotland with Robert Bowes to discuss border affairs and incidents at Swinburn and Eslington Road involving the Scottish border warden Sir Robert Kerr of Cessford (later Lord Roxburgh), and they met James VI first at Linlithgow Palace, and on 20 June in the garden of Falkland Palace. He was appointed treasurer of Berwick-upon-Tweed from 1598 to 1603.
In June 1599 William became concerned by the activities of a private English gentlemen, Edmund Ashfield, who had obtained permission to visit Scotland. William assisted in Ashfield's kidnap and rendition to England and faced an angry Edinburgh mob at his lodging. William was recalled soon after.
Around the year 1600 William married Isabel Wray, daughter of the English judge Sir Christopher Wray.