The Scientific Research Institute of Steel (Russian: Научно-исследовательский институт стали), also known as NII Stali, 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.