Countess of Derby

The Countess of Derby usually refers to the wife or widow of an Earl of Derby, such as:
 * Margaret Peverell, Countess of Derby (c. 1144–1154), English noblewoman
 * Margaret Clifford, Countess of Derby (1540–1596), great-granddaughter of King Henry VII of England
 * Alice Spencer, Countess of Derby (1559–1637), English noblewoman
 * Elizabeth de Vere, Countess of Derby (1575–1627), English noblewoman and daughter of Edward de Vere, 17th Earl of Oxford
 * Charlotte Stanley, Countess of Derby (1599–1664), English noblewoman famous for her role against the siege of Lathom House
 * Elizabeth Smith-Stanley, Countess of Derby (1753–1797), English peeress
 * Elizabeth Farren, Countess of Derby (c. 1759–1829), wife of Edward Smith-Stanley, 12th Earl of Derby
 * Mary Catherine Stanley, Countess of Derby (1824–1900), English grande dame and political hostess
 * Emma Caroline Smith-Stanley, Countess of Derby (died 1876), wife of Edward Smith-Stanley, 14th Earl of Derby
 * Alice Stanley, Countess of Derby (1862–1957), wife of Edward Stanley, 17th Earl of Derby
 * Caroline Stanley, Countess of Derby (born 1963), wife of Edward Stanley, 19th Earl of Derby