Juan de Mancicidor (died before 30 May 1618) was secretary of state and war to the Archduke Albert from 1596 to his death in 1618.

Mancicidor served in Madrid under Philip II's secretary of state, Juan de Idiáquez.

When Archduke Albert was sent to the Low Countries as Governor General in 1596, Mancicidor accompanied him as his secretary of state and war.

As Secretary of State he was responsible for the confidential correspondence between the Archduke and King Philip III of Spain, royal ministers, Spanish ambassadors at their various postings, the governor of Milan, the Viceroy of Naples, and other dignitaries.

He died before 30 May 1618, when the christening of his youngest child took place, but the exact date is unknown.