George William MacArthur Reynolds (23 July 1814 – 19 June 1879) was a British author and journalist.
He was born in Sandwich, Kent, the son of Captain Sir George Reynolds, a flag officer of the Royal Navy. Reynolds was educated first at Dr. Nance's school in Ashford, Kent, and then attended the Royal Military College, Sandhurst. He was intended for a career in the British Army, but on the death of his parents during 1829 and his subsequent inheritance, he decided to quit the military and devote himself instead to literary pursuits. He left Sandhurst on 13 September 1830 and for the next few years he traveled a great deal, particularly in France, and became a naturalised French citizen. He began residence in Paris in 1834, where he started a daily English newspaper. The venture failed, and Reynolds returned bankrupt to England in 1836.
Reynolds served as editor of The Teetotaler (a weekly journal advocating teetotalism) beginning in 1840.
Reynolds was a prolific writer of popular fiction starting from The Youthful Imposter, published in 1835. Virtually forgotten now, during his lifetime he was more read than Dickens or Thackeray; in his obituary, the trade magazine The Bookseller called Reynolds "the most popular writer of our times" ("Obituary" 600). His best-known work was the long-running serial The Mysteries of London (1844), which borrowed liberally in concept from Eugène Sue's Les Mystères de Paris (The Mysteries of Paris). It sold 40,000 copies a week in penny instalments and more than a million copies cumulatively before it was issued in bound volumes, enjoying an international circulation in French, German, Italian, and Spanish translations. Although it was outlawed by the authorities, the German version achieved the status of a cult favourite on the Russian black market.