Cartimandua or Cartismandua (reigned c. AD 43 – c. 69) was a 1st-century queen of the Brigantes, a Celtic people living in what is now northern England.

She is recorded betraying the Celtic chieftain Caratacus, insincerely offering him sanctuary, but instead turning him in to the Romans in exchange for wealth.

She subsequently engaged in extended military conflict with her ex-husband as he staged revolts against her multiple times, eventually losing to him.

[3] Tacitus wrote: "She had later strengthened her power when she was credited with having captured King Caratacus by treachery and so furnished an adornment for the triumph of Claudius Caesar.

[9] Tacitus wrote: "She grew to despise her husband Venutius, and took as her consort his squire Vellocatus, whom she admitted to share the throne with her.

So Venutius, calling in aid from outside and at the same time assisted by a revolt of the Brigantes themselves, put Cartimandua into an extremely dangerous position.

Then she asked the Romans for protection, and in fact some companies of our foot and horse, after meeting with indifferent success in a number of engagements, finally succeeded in rescuing the queen from danger.