Pachacuti Inca Yupanqui or Pachacutec (in hispanicized spellings) or Pachakutiq Inka Yupanki (Quechua) is the ninth Sapa Inca (1438–1471/1472) of the Kingdom of Cusco which he transforms into the Inca Empire (Tawantinsuyu).

Most archaeologists now believe that the famous Inca site of Machu Picchu was built as an estate for Pachacuti.

In Quechua Pachakutiq means "he who shakes the earth" and Yupanki means "with honor".

During his reign, Cusco grows from a hamlet into an empire that can compete with, and eventually overtake, the Chimú.

He begins an era of conquest that, within three generations, expands the Inca dominion from the valley of Cusco to nearly the whole of western South America.