The 2016 Estoril Open (also known as the Millennium Estoril Open for sponsorship purposes) was a tennis tournament played on outdoor clay courts. It was the second edition of the Estoril Open, and part of the ATP World Tour 250 series of the 2016 ATP World Tour. The event took place at the Clube de Ténis do Estoril in Cascais, Portugal, from 25 April until 1 May 2016. Unseeded Nicolás Almagro won the singles title.
See main article: 2016 Estoril Open – Singles.
Nicolás Almagro defeated Pablo Carreño Busta, 6–7(6–8), 7–6(7–5), 6–3See main article: 2016 Estoril Open – Doubles.
Eric Butorac / Scott Lipsky defeated 
Łukasz Kubot / Marcin Matkowski, 6–4, 3–6, [10–8]| Country | Player | Rank1 | Seed | |
|---|---|---|---|---|
 France | Gilles Simon | 18 | 1 | |
 Australia | Nick Kyrgios | 20 | 2 | |
| France | Benoît Paire | 22 | 3 | |
| João Sousa | 34 | 4 | ||
| Spain | Guillermo García-López | 37 | 5 | |
| Borna Ćorić | 41 | 6 | ||
 Argentina | Leonardo Mayer | 45 | 7 | |
| Spain | Pablo Carreño Busta | 49 | 8 |
The following players received wildcards into the singles main draw:
The following players received entry from the qualifying draw:
Gilles Müller → replaced by Daniel Gimeno-Traver Tommy Robredo → replaced by Benjamin Becker Jo-Wilfried Tsonga → replaced by Michael Berrer
Dmitry Tursunov → replaced by 
Rogério Dutra Silva| Country | Player | Country | Player | Rank1 | Seed | |
|---|---|---|---|---|---|---|
| Poland | Łukasz Kubot | Poland | Marcin Matkowski | 45 | 1 | |
| Treat Huey |  Belarus | Max Mirnyi | 49 | 2 | ||
| Spain | Spain | |||||
| United States | Eric Butorac | United States | Scott Lipsky | 91 | 4 | |
 Israel | Jonathan Erlich |  United Kingdom | Colin Fleming | 107 | 5 |
The following pairs received wildcards into the doubles main draw:
The following pair received entry as alternates:
Marc López (abductor injury)
