The 2011 Siemens Open was a professional tennis tournament played on clay courts. It was part of the Tretorn SERIE+ of the 2011 ATP Challenger Tour. It was the 19th edition of the tournament. It took place in Scheveningen, Netherlands between July 4 and July 10, 2011.
| Country | Player | Rank1 | Seed | |
|---|---|---|---|---|
 Turkey | Marsel İlhan | 105 | 1 | |
 Belgium | Steve Darcis | 106 | 2 | |
 France | Éric Prodon | 107 | 3 | |
| France | Marc Gicquel | 119 | 4 | |
| France | Stéphane Robert | 120 | 5 | |
 Russian Federation | Teymuraz Gabashvili | 129 | 6 | |
 Czech Republic | Ivo Minář | 132 | 7 | |
| Julian Reister | 135 | 8 |
The following players received wildcards into the singles main draw:
Ivo MinářThe following players received entry from the qualifying draw:
See main article: 2011 The Hague Open – Singles. Steve Darcis def. Marsel İlhan, 6–3, 4–6, 6–2
See main article: 2011 The Hague Open – Doubles. 
Colin Ebelthite / Adam Feeney def. Rameez Junaid / Sadik Kadir, 6–4, 6–7(5–7), [10–7]
