Maria of Aragon
Queen consort of Castile and León
Tenure	c. 1420–18 February 1445 (1445-02-18)
Born	(1403-02-24)24 February 1403 Crown of Castile
Died	18 February 1445(1445-02-18) (aged 41) Villacastín, Crown of Castile
Burial	Santa María de Guadalupe, Spain
Spouse	John II of Castile
Issue Detail	Catherine, Princess of Asturias Eleanor, Princess of Asturias Henry IV of Castile
House	Trastámara
Father	Ferdinand I of Aragon
Mother	Eleanor of Alburquerque

Maria of Aragon ((1403-02-24)24 February 1403 – (1445-02-18)18 February 1445) was the Queen of Castile as the first wife of King John II from their marriage in 1420 until her death in 1445. She was the daughter of Ferdinand I of Aragon and Eleanor of Alburquerque.

Maria was married by her brother in his ambition to place his father's issue on the thrones of Castile and Aragon. The marriage took place in simplicity. Maria was occasionally politically active on behalf of her brothers, the princes of Aragon; she disregarded her husband's policy in favor of her brothers and the relationship between Maria and John was somewhat tense.

After her death on 18 February 1445, her husband married Isabella of Portugal and they became the parents of Isabella I of Castile. Maria has no descendants today, her line having gone extinct within a few decades of her death.

Maria and John II of Castile had four children:

• Catherine, Princess of Asturias ((1422-10-05)5 October 1422–(1424-09-17)17 September 1424).
• Eleanor, Princess of Asturias ((1423-09-10)10 September 1423–(1425-08-22)22 August 1425).
• Henry IV of Castile ((1425-01-05)5 January 1425–(1474-12-11)11 December 1474). First married Blanche II of Navarre and later married Joan of Portugal.
• Infanta Maria (c. 1428–c. 1429).