Hrastnik (, German: Hrastnigg) is a town in the Central Sava Valley in central Slovenia. It is the seat of the Municipality of Hrastnik. The area is part of the traditional region of Styria. The entire municipality is now included in the Central Sava Statistical Region.
In the past, the majority of locals were employed in the glass, coal, or chemical industry. Today the glass and chemicals factories still operate, but many people also go to work in neighbouring towns such as Trbovlje or Zagorje ob Savi. Coal started being mined in Hrastnik in 1822. Production was limited until 1849, when the town was connected to the Austrian Southern Railway. Hrastnik is also known for glass manufacturing. The first school was opened in Hrastnik in 1860. It was originally operated for miners' children at the miners' restaurant but became a public school in 1872. A separate school building was built in 1879. A German-language school was established in 1907 and operated until the end of the First World War.
