Guillermo Thorndike Losada (April 25, 1940 – March 9, 2009) was a Peruvian journalist and writer, who helped to found several important newspapers within Peru.
Thorndike helped to found La República, one of the country's main national dailies, and was the founder of Cronicawan, the first nationally circulated Quechua language newspaper in Peru's history.
He has been called one of the most important Peruvian journalists of the past 40 years.