Admiral Sir William Penn (1621–1670) was an English naval officer known for his significant contributions to the Royal Navy during the 17th century. He played a crucial role in various naval battles, including the Second Anglo-Dutch War, and was recognized for his leadership and strategic skills. His naval career helped establish England's maritime power. In addition to his military achievements, Penn is also known as the father of William Penn, the founder of Pennsylvania. His legacy includes not only his naval service but also the influence he had on the early development of American colonies through his son's endeavors.