| Type: | Stadt |
| Image Coa: | DEU Horstmar COA.svg |
| Coordinates: | 52.0806°N 7.3083°W |
| Image Plan: | Horstmar in ST.svg |
| State: | Nordrhein-Westfalen |
| Region: | Münster |
| District: | Steinfurt |
| Elevation: | 77 |
| Area: | 45 |
| Postal Code: | 48612 |
| Area Code: | 02558 |
| Licence: | ST |
| Gemeindeschlüssel: | 05 5 66 024 |
| Website: | www.horstmar.de |
| Mayor: | Robert Wenking[1] |
| Leader Term: | 2020 - 25 |
| Party: | CDU |
Horstmar is a German town, located in North Rhine-Westphalia in the Steinfurt district, approx. 25km (16miles) north-west of Münster.
Its castle was built as early as the 9th century; the first mention of Horstmar is as early as the early 11th century. The city of Horstmar was built to the south of this castle. During the Thirty Years' War the castle was destroyed by order of the Hessian lieutenant Carl von Rabenhaupt.
The city council consists of 22 councillors and the mayor.