The Scientific Research Institute of Steel (Russian: Научно-исследовательский институт стали), also known as NII Stali (Russian: НИИ стали), is a Russian research institute (NII) located in the capital city of Moscow.

The institute occupies an area of 64,000 m², including production areas of 40,000 m². It is organized as a joint-stock company and was founded in 1942.

The company is known for its military products, including tank armor and military helmets. Since 2023, it also produces anti-fragmentation blankets.

• Official website
• «Калашников» начал серийное производство титановых бронешлемов «Эльбрус-Т» (in Russian)
• «Калашников»: «Эгида-У» от НИИ Стали защищает от осколков на 100% (in Russian)

55°53′31″N 37°33′08″E / 55.8919°N 37.5522°E / 55.8919; 37.5522