Alonzo de Santa Cruz (or Alonso, Alfonso) (1505 – 1567) was a Spanish cartographer, mapmaker, instrument maker, historian and teacher.

[3] Alonzo de Santa Cruz, described cosmography as a way of making a painting of the earth, "because (gra)phia is the same as painting and cosmos is world"[4][5] In 1530, Alonzo de Santa Cruz produced the first map of magnetic variations from true north.

Alonzo de Santa Cruz designed new nautical instruments,[6] was interested in navigational methods, and wrote about John Cabot's method for finding longitude which made use of the declination of the sun, observed with the quadrant.

[8] He also produced the Islario general de todas las islas del mundo (sometimes called the Islario General), a map and document describing the world's islands, at the request of King Philip II in 1542.

He also continued Hernando del Pulgar's work titled, History of the Catholic Monarchs.