The Estoril Open (also known as the Millennium Estoril Open for sponsorship purposes) is an ATP clay court tennis tournament in Portugal. The event takes place at the sports complex of Clube de Ténis do Estoril in Cascais. The tournament was created in 2015 to replace the historic Portugal Open, which was canceled due to lack of sponsorships. The tournament was created by former Dutch tennis player Benno van Veggel and Portuguese football agent Jorge Mendes.