Gregor von Helmersen (September 29, 1803 - February 3, 1885), Russian geologist, was born at Laugut-Duckershof, near Dorpat.

He received an engineering training and became major-general in the corps of Mining Engineers. In 1837 he was appointed professor of geology in the mining institute at St Petersburg. He was author of numerous memoirs on the geology of Russia, especially on the coal and other mineral deposits of the country; and he wrote also some explanations to accompany separate sheets of the geological map of Russia.

His geological work was continued to an advanced age, one of the later publications being Studien über die Wanderblöcke und die Diluvialgebilde Russlands (1869 and 1882). Most of his memoirs were published by the Imperial Academy of Sciences at St Petersburg.