George Robert Sims (1847 – 1922) was an English journalist, poet, dramatist, novelist and bon vivant.

Sims began writing lively humour and satiric pieces for Fun magazine and The Referee, but he was soon concentrating on social reform, particularly the plight of the poor in London's slums. A prolific journalist and writer he also produced a number of novels.

Sims was also a very successful dramatist, writing numerous plays, often in collaboration, several of which had long runs and international success. He also bred bulldogs, was an avid sportsman and lived richly among a large circle of literary and artistic friends. Sims earned a fortune from his productive endeavours but had gambled most of it away by the time of his death.

Sims was born in Kennington, London, England. His parents were George Sims, a prosperous merchant, and Louisa Amelia Ann Stevenson Sims, president of the Women's Provident League. Sims was the oldest of six children, who were exposed to their parents' cosmopolitan artistic and progressive friends, including suffragists. He grew up in Islington, London, and his mother often took him to the theatre. He was educated in Eastbourne and then Hanwell Military College and the University of Bonn. He had begun to write poetry at the age of ten, and at Bonn he wrote some plays, including an adaptation of Dr. Wespe by Benedix. He completed his studies in Germany and France, where he also became interested in gambling. In Europe, he translated Balzac's Contes drôlatiques, which was published in 1874 by Chatto and Windus; but it was considered too racy and was withdrawn, only to be reissued in 1903.
Sims was married three times and was twice a widower. In 1876, he married Sarah Elizabeth Collis (b. 1850).

In 1888, he married Annie Maria Harriss (b. 1859). Finally, in 1901, he married Elizabeth Florence Wykes (b. 1873) who survived him. None of these marriages produced any children. The Times wrote in Sims's obituary that
"so attractive and original was the personality revealed in his abundant output—for he was a wonderfully hard worker—that no other journalist has ever occupied quite the same place in the affections not only of the great public but also of people of more discriminating taste.... Sims was indeed a born journalist, with the essential flair added to shrewd common sense, imagination, wide sympathies, a vivid interest in every side of life, and the most ardent patriotism....

He was [also] a highly successful playwright...