George Williams Cassidy (April 25, 1836 – June 24, 1892) was a Democratic Party politician in California and Nevada who served two terms in the United States House of Representatives.
Cassidy was born near Paris, Kentucky, on April 25, 1836, and his family moved to Missouri when he was five years old.
Active in politics from early adulthood, he became a member of the California Democratic Party's central committee.
In 1880 he ran successfully for Nevada's At-Large seat in the United States House of Representatives.
In 1886, he was appointed a national bank examiner for Nevada, Utah, California, and Colorado, and he served until 1890.