Georg Wilhelm Steller (10 March 1709 – 14 November 1746) was a German-born naturalist and explorer who contributed to the fields of biology, zoology, and ethnography.

He participated in the Great Northern Expedition (1733–1743) and his observations of the natural world helped the exploration and documentation of the flora and fauna of the North Pacific region.

In 1734, he joined the Russian Academy of Sciences as a physician, eventually being selected to accompany Bering's expedition to the uncharted waters between Siberia and North America.

Two years after Messerschmidt's death, Steller married his widow and acquired notes from his travels in Siberia not handed over to the Academy.

Steller embraced that role and finally reached Okhotsk and the main expedition in March 1740 as Bering's ships, the St. Peter and St. Paul, were nearing completion.

When Bering summoned him to join the voyage in search of America and the strait between the two continents, serving in the role of scientist and physician, Steller crossed the peninsula by dog sled.

After considerable time lost, they turned northeast and made landfall in Alaska at Kayak Island on Monday 20 July 1741.

Although Steller tried to treat the crew's growing scurvy epidemic with leaves and berries he had gathered, officers scorned his proposal.

On the return journey, with only 12 members of the crew able to move and the rigging rapidly failing, the expedition was shipwrecked on what later became known as Bering Island.

Some of his journals, which reached the academy and were later published by Peter Simon Pallas, were used by other explorers of the North Pacific, including Captain Cook.

Of particular note were the only detailed behavioral and anatomical observations of Steller's sea cow, a large sirenian mammal that once ranged across the Northern Pacific during the Ice Ages, but whose surviving relict population was confined to the shallow kelp beds around the Commander Islands, and which was driven to extinction within 30 years of discovery by Europeans.