Sir Robert Ducie, 1st Baronet (1575 – June 1634) was an English merchant who was Lord Mayor of London in 1631.
He was banker to King Charles I. Ducie was the eldest surviving son of Henry Ducie, merchant of London and his wife Mary Hardy.
On 4 December 1620, he was elected an alderman of the City of London for Farringdon Without ward.
He became president of St Bartholomew's Hospital in 1628 and was created a Baronet on 28 November 1629.
[1] Ducie accumulated immense wealth as a merchant, and despite having lost £80,000 when the King was driven from London during the Civil War, he was reputedly worth more than £400,000[2] at his death.