Mechtilde of Holstein [a] (c. 1218 – 1288) was a Danish queen consort, married to King Abel of Denmark and later to Birger Jarl, Regent of Sweden.

[3] On 25 April 1237 she was married to Duke Abel of Schleswig, King Valdemar's second eldest son, as part of a settlement between the two houses.

Abel died two years later in 1252, and was succeeded by his brother Christopher rather than her son Valdemar, who was imprisoned by the Archbishop of Cologne at the time.

[4] She made a pact with Jacob Erlandsen, archbishop of Lund, and then broke her vows from the convent by marrying the Swedish regent Birger Jarl in 1261.

[4] This caused much resentment in Denmark, where she was labeled the "daughter of the Devil" and accused of destroying letters from the Pope and emperor to King Valdemar.