Aimo Johannes Lahti (April 28, 1896 – April 19, 1970) was a self-taught Finnish weapons designer.
Of the 50 weapons he designed, the best known is the Suomi M-31 SMG.
Other well-known weapon designs of his include the Lahti-Saloranta M/26 LMG, Lahti L-35 pistol, and Lahti L-39 anti-tank rifle.
Lahti also designed the 7,62 ITKK 31 VKT anti-aircraft machine gun and the 20 ITK 40 VKT anti-aircraft cannon.
His work is considered decisive in defending Finnish independence and increasing trust in the reliability of domestic weapons produced there.