Amelia Alderson was the daughter of James Alderson, a physician, and Amelia Briggs of Norwich, England. She was a cousin of notable judge Edward Hall Alderson, with whom she corresponded throughout her life, and also a cousin of notable artist Henry Perronet Briggs.
Miss Alderson had inherited radical principles and was an ardent admirer of John Horne Tooke. She was close to activists John Philip Kemble, Sarah Siddons, William Godwin and Mary Wollstonecraft.
In 1798 Alderson married John Opie, the painter. The nine years of her married life before her husband's death were happy, although her husband did not share her love of society. With his encouragement, in 1801 she completed a novel entitled Father and Daughter, which showed genuine fancy and pathos.
Amelia Opie published regularly after that. In 1802 she completed a volume of verse. Additional books followed: Adeline Mowbray (1804), Simple Tales (1806), Temper (1812), Tales of Real Life (1813), Valentine's Eve (1816), Tales of the Heart (1818), and Madeline (1822).
Opie wrote The dangers of Coquetry at age 18. Her novel Father and Daughter (1801) is about misled virtue and family reconciliation. Encouraged by Mary Wollstonecraft, she wrote Adeline Mowbray (1804), an exploration of relationship between mother and daughter. Adeline Mowbray uses frank language to deliver the moral that the desires of women as much as those of men can override their families' wishes and thus jeopardise their future
Amelia Opie divided her time between London and Norwich. She was a friend of writers Sir Walter Scott, Richard Brinsley Sheridan and Madame de Stael.
In 1825, through the influence of Joseph John Gurney, she joined the Society of Friends. After a book entitled Detraction Displayed and contributions to periodicals, she wrote nothing more. The rest of her life was spent travelling and working at charity.
Even late in life, Opie maintained connections with writers, for instance receiving George Borrow as a guest. After a visit to Cromer, a seaside resort on the North Norfolk coast, she caught a chill and retired to her bedroom. A year later on 2 December 1853, she died at Norwich. Ms. Opie was said to retain her vivacity to the last. She was buried at the Gildencroft Quaker Cemetery, Norwich.
A biography of her, A Life, by Miss C.L. Brightwell, was published in 1854.