Catherine Eddowes (14 April 1842 – 30 September 1888) was the fourth of the canonical five victims of the notorious unidentified serial killer known as Jack the Ripper, who is believed to have killed and mutilated at least five women in the Whitechapel and Spitalfields districts of London from late August to early November 1888.

Eddowes was murdered in the early hours of Sunday 30 September within the City of London. She was the second woman killed within an hour; the night having already seen the murder of Elizabeth Stride within the jurisdiction of the Metropolitan Police. These two murders are commonly referred to as the "double event"; a term which originates from the content of the "Saucy Jacky" postcard received at the Central News Agency on 1 October.

A part of a left human kidney, accompanied by a letter addressed From Hell and postmarked 15 October, was later sent to the chairman of the Whitechapel Vigilance Committee, George Lusk. The author of this letter claimed the section of kidney was from Eddowes, whose left kidney had been removed, and that he had fried and eaten the other half. Most experts, however, do not believe this kidney actually originated from Eddowes's body.

Catherine Eddowes was born in Graiseley Green, Wolverhampton on 14 April 1842, the sixth of twelve children born to tinplate worker George Eddowes and his wife, Catherine (née Evans), who worked as a cook at the Peacock Hotel.

The family moved to London a year after Eddowes's birth, where her father obtained employment with a firm named Perkins and Sharpus in Bell Court, within the City of London. The family initially resided at 4 Baden Place, Bermondsey, and later relocated to 35 West Street. Here, Eddowes was educated at St. John's Charity School in Potter's Field. By 1851, the family had relocated to 35 West Street. Her mother ultimately bore eleven other children, although only ten of her twelve children survived. She herself died of tuberculosis on 17 November 1855 at the age of 42.

By 1857, both of Eddowes's parents had died, resulting in Eddowes (then aged 15) and three of her siblings being admitted as orphans to a Bermondsey workhouse. All four Eddowes siblings admitted to this workhouse attended a local industrial school in efforts to teach them a trade. Via this initiative, one of Eddowes's older sisters, Emma, and an aunt secured employment for her as a tinplate stamper at the Old Hall Works in Wolverhampton. She relocated to Wolverhampton, residing with her aunt in Bilston Street and working at the Old Hall Works as she continued her education at Dowgate Charity School.

Within months of obtaining this employment, Eddowes was fired from her job, possibly after being caught stealing. Eddowes's loss of employment is believed to have caused tensions between her and her aunt, as shortly thereafter, she relocated from Wolverhampton to Birmingham, where she briefly lived with an uncle named Thomas Eddowes, who worked as a shoemaker. Eddowes soon found employment as a tray polisher at a firm in Legge Street in Birmingham, although after approximately four months, she chose to return to Wolverhampton, where she resided with her grandfather, who found work for her as a tinplate stamper. Nine months later, she again moved to Birmingham.

Eddowes was 5 ft 0 in (1.52 m) tall, slim, with dark, wavy auburn hair and hazel eyes. Friends later described her as "a very jolly woman, always singing" and an "intelligent and scholarly [individual], but possessed of a fierce temper."