Sir Thomas Hewett, 1st Baronet (1605 – 4 August 1662) was an English landowner of the Civil War period, who briefly sat in Parliament for Windsor.
In 1635, he purchased the manor of Sawbridgeworth (Sayesbury and Pishobury) from Lionel Cranfield, 1st Earl of Middlesex, Arthur Brett, and Nicholas Harman[3] for £16,500.
He succeeded to his father's estate in 1637, and in the same year became a trustee for Lady Elizabeth, widow of Sir Robert Bevill (d. 1634).
In 1642, he was named to the commission of assessment for the county, and made a commissioner of array and JP, sitting on the Hertfordshire Bench until about 1650.
Upon the English Restoration, he was created a baronet on 19 July 1660, served as commissioner of militia for the county, and was chosen sheriff of Hertfordshire again in November.