Robert Baldwin Ross (25 May 1869 – 5 October 1918) was a British journalist, art critic and art dealer, best known for his relationship with Oscar Wilde, to whom he was a devoted friend, lover and literary executor. A grandson of the Canadian reform leader Robert Baldwin, and son of John Ross and Augusta Elizabeth Baldwin, Ross was a pivotal figure on the London literary and artistic scene from the mid-1890s to his early death, and mentored several literary figures, including Siegfried Sassoon. His open homosexuality, in a period when male homosexual acts were illegal, brought him many hardships.

Ross was born in Tours, France. His mother, Elizabeth Baldwin, was the eldest daughter of Robert Baldwin, a Toronto lawyer and politician who in the 1840s, together with his political partner Louis Hippolyte Lafontaine, led Canada to autonomy from Britain. Ross's father, John Ross, was a Baldwinite and a Toronto lawyer who had a very successful political career, serving as Solicitor General for Upper Canada, Attorney General, Speaker of the Legislative Council, President of the Legislative Council, director, and, for a time, president, of the Grand Trunk Railway, and Canadian senator. He became Speaker of the Senate in 1869.

Ross was the youngest of five children, with two sisters, Mary and Maria, and two brothers, John and Alexander. The family moved to Tours, France, in 1866 while Elizabeth was pregnant with Maria, who was born in 1867, the year of Canadian Confederation. John fulfilled his duties as senator largely in absentia until he was chosen as Speaker of the Senate in 1869, the year of Robbie's birth, making his return to Canada unavoidable. The rest of the family followed in 1870. John died in January 1871 and Elizabeth moved the family to London the following April.

In 1888, Ross was accepted at King's College, Cambridge, where he became a victim of bullying, probably because of his homosexuality, of which he made no secret, and perhaps also his outspoken journalism in the university paper. Ross caught pneumonia after being dunked in a fountain by other students who had, according to Ross, the full support of Arthur Augustus Tilley, the Junior Tutor of King's. After recovering, he fought for and received an apology from his fellow students. He also sought Tilley's dismissal. The college refused to punish Tilley, who resigned as Junior Tutor. Ross dropped out and soon revealed his sexuality to his parents.

Ross found work as a journalist and critic but he did not escape scandal. He is believed to have become Oscar Wilde's first male lover in 1886, even before he went to Cambridge. In 1893, a few years before Wilde's imprisonment, Ross had a sexual relationship with a boy of sixteen, the son of friends. The boy confessed to his parents that he had engaged in sexual activity with Ross and also admitted to a sexual encounter with Lord Alfred Douglas while he was a guest at Ross's house. After a good deal of panic and frantic meetings with solicitors, the parents were persuaded not to go to the police, since at that time their son might be seen as equally guilty and face the possibility of going to prison.

On 1 March 1895, Wilde, Douglas, and Ross approached a solicitor, Charles Octavius Humphreys, with the intention of suing the Marquess of Queensberry, Douglas's father, for criminal libel. Humphreys asked Wilde directly whether there was any truth to Queensberry's allegations of homosexual activity between Wilde and Douglas, to which Wilde replied “No.” Humphreys applied for a warrant for Queensberry's arrest, and approached Sir Edward Clarke and Charles Willie Mathews to represent Wilde. His son, Travers Humphreys, appeared as junior counsel for the prosecution in the subsequent case of Wilde v Queensberry.

The libel hearings unearthed evidence that caused Wilde to drop his charges and led to an arrest warrant for him on charges of sodomy and gross indecency. Ross found Wilde at the Cadogan Hotel, in Knightsbridge, with Reginald Turner. Both men advised Wilde to get a boat-train to France, but he refused. His mother had advised him to stay and fight, and Wilde reportedly said: "The train has gone. It's too late." Following Wilde's imprisonment in 1895, Ross went abroad but he returned to offer both financial and emotional support to Wilde during his last years. Ross remained loyal to Wilde and was with him when he died in Paris on 30 November 1900.

Ross became Wilde's literary executor, which meant that he had to track down and purchase the rights to all of Wilde's texts, which had been sold off along with Wilde's possessions when Wilde was declared bankrupt. It also meant fighting the rampant trade in black market copies of his books and, in particular, books, usually erotic, that Wilde did not write, but which were published illegally under his name.^{[citation needed]}