Siedlec was formerly part of the German Empire. In the German Empire, the place was called Alt Siedel.
The place is now called Siedlec and belongs to Poland.
| Historical place name | Country | Administration | Time |
|---|---|---|---|
| Schedlitz | German Empire | Groß Strehlitz | 1936 |
| Alt Siedel | German Empire | Groß Strehlitz | 1939 |
| Siedlec | Under Polish administration | Strzelce Opolskie | 1945 |
| Siedlec | Poland | Opole | 1992 |