Juan de Grijalva (born around 1489 in Cuéllar - January 21, 1527) was a Spanish conquistador. Some authors said he was from the same family as Diego Velázquez.

He went to Hispaniola en 1508 and to Cuba in 1511.

He was one of the earliest to explore the shores of Mexico. He left Cuba with four ships in April 1518. According to Hernán Cortés, 170 people went with him, but according to Pedro Mártir, there were 300 people.

The main pilot was Antón de Alaminos, the other pilots were Juan Álverez (also known as el Manquillo), Pedro Camacho de Triana, and Grijalva.

Other members included Francisco de Montejo, Pedro de Alvarado, Juan Díaz, Francisco Peñalosa, Alonso de Ávila, Alonso Hernández, Julianillo, Melchorejo, Antonio Villafaña.

He arrived on May 1, at the Cape of Guaniguanico in the South of Mexico.

Río Grijalva (Mexico) was named after him. Bernal Díaz del Castillo wrote about the travell of Juan de Grijalva in his book.

He died in Nicaragua in 1527.