Knut Eilevsson Steintjønndalen (c. 1850 – December 2, 1902) was a Norwegian Hardanger fiddle maker from Bø in Telemark, Norway.
He married and bought the Langkås farm in the Folkestad neighbourhood, and he founded a workshop there.
He experimented with making the tone more powerful by increasing the thickness of the soundboard and bottom.
However, his greatest reputation came from the exquisite ornamentation on his instruments.
The musicians that he created instruments for included Nils Tjoflot.