Thomas Blood (1618 - August 24, 1680) was an English Colonel who is best known for attempting to steal the Crown Jewels of England from the Tower of London in 1671.

Blood was born in County Clare in Ireland. Like many he was educated in England. He returned to Ireland at Oliver Cromwell's request, receiving land grants as payment for his service. When the monarchy was restored in 1660, these grants were cancelled, and he lost most of his income. He conspired to kidnap James Butler, 1st Duke of Ormonde, the Lord Lieutenant of Ireland. The plan was foiled, but Blood managed to evade the authorities and escape to the Netherlands. He tried to abduct Butler again, in 1670, but this also failed.

In 1671 Blood made his infamous attempt to steal the Crown Jewels. Over several weeks he befriended the Jewel Keeper, Talbot Edwards. On May 9, 1671, having earned the trust of Edwards, he convinced him to show the jewels to his friends, who then knocked Edwards to the floor, where he was bound and gagged. Edwards, however, somehow managed to sound the alarm, and Blood and his co-conspirators were captured while trying to escape with the jewels. Blood never even managed to get outside the Tower

King, Charles II met with Blood after the latter's trial. For reasons not fully known, the King pardoned Blood, returned the original land grants, and granted him a pension of five hundred pounds per annum.

Although Charles II was known as the Merrie Monarch, he is unlikely to have released Blood merely as a reward for his derring-do. Historians have noted the Royal money troubles, and have surmised that Blood was acting under orders. The jewels, most of which were made for Charles II may have been destined to be broken up and sold on the continent and the proceeds used to refill the royal treasury.

Another theory is that the attempts on Ossory were instigated by the Duke of Buckingham. Ossory and Buckingham were feuding, perhaps Blood's pardon was a warning that Buckingham, as the King's favourite and chief minister, was immune.