Carlos I may refer to:
*
Carlos I of Spain
Charles V, french: Charles Quint, it, Carlo V, nl, Karel V, ca, Carles V, la, Carolus V (24 February 1500 – 21 September 1558) was Holy Roman Emperor and Archduke of Austria from 1519 to 1556, King of Spain ( Castile and Aragon) fro ...
(1500–1558), also Charles V of the Holy Roman Empire
*
Carlos I of Portugal
''Dom'' Carlos I (; English: King Charles of Portugal; 28 September 1863 – 1 February 1908), known as the Diplomat ( pt, o Diplomata), the Martyr ( pt, o Martirizado), and the Oceanographer ( pt, o Oceanógrafo), among many other names, was ...
(1863–1908), King of Portugal
*
Juan Carlos I of Spain
Juan Carlos I (;,
* ca, Joan Carles I,
* gl, Xoán Carlos I, Juan Carlos Alfonso Víctor María de Borbón y Borbón-Dos Sicilias, born 5 January 1938) is a member of the Spanish royal family who reigned as King of Spain from 22 Nov ...
(born 1938), King of Spain
{{hndis, Carlos 01