Grigory Yefimovich Grumm-Grzhimaylo (Russian: Григо́рий Ефи́мович Грумм-Гржима́йло, 1860–1936) was a Russian entomologist, best known for his expeditions to Central Asia (Pamir, Bukhara, Tian-Shan, Kan-su, and Kukunor), West Mongolia and Tuva, and the Russian Far East. In botanical literature his name is sometimes spelled as Grigor Efimowitsch Grumm-Grzhimailo.
Born in St. Petersburg, his early interest was in the phylloxera problem in the vineyards of N. Y. Danilevsky. He wrote his first scientific work at the age of 21 on some lepidoptera of the Crimea (1882, vol. 8 of the 'Proceedings of the Russian Entomological Society).
He was associated with Professor M. N. Bogdanov at the St. Petersburg Museum and contributed many of his own collections to it. He also studied the collections of the museum that had been made by Nikolai Przhevalsky, Grigory Potanin, Pyotr Semyonov-Tyan-Shansky, and other explorers of Central Asia.
From 1882, Grumm-Grzhimaylo studied Lepidoptera from the Bessarabia, Podolia Governorate, Crimea, and the Baltic and got interested in zoogeography. While collecting near Sarepta, he met the German collector Rückbeil. He also met the Grand Duke Nicholas Mikhailovich Romanov who suggested that he should publish his work. He also promised his support for an expedition to the Pamirs. In 1884, he started his first Pamir expedition on which he visited the Alai Mountains, ascending the Trans-Alai range via Pass Tersagarsky to reach the upper Muksu River to reach Fedchenko's glacier. He visited Lake Karakul and returned. He collected 12,000 specimens, thirty of which were new to science. Spurred by the interest to his work, he made a second expedition in 1885 visiting Karateghin, Darvaz, Bukhara Khanate, Ghissar, Kulyab, Beldzhuan, Shakhrisiabz, Karshi, Guzara, Shirabad, Kabadian, and Kurgan-Tyube. This time he collected 20,000 specimens of insects.