Has there ever been a female dictator?

Sure, there have been quite a few. Keep in mind that the term "dictator" means a single ruler who assumes whole and absolute power. Following is a list of a few female dictators:

• Cleopatra (Egyptian Pharaoh)
• Boudica (Queen of the Iceni)
• Elizabeth I (British Monarch)
• Catherine the Great (Russian Czarina)
• Indira Ghandi (Prime Minister of India)
• Amivi Gama (East Timor President for Life)
• Empress Dowager Cixi (ruler of the Qing Dynasty of China from 1861 to 1908)

And then the various Empresses of Japan:

• Empress Suiko (554-628)
• Empress Kōgyoku (594-661)
• Empress Saimei (594-661)
• Empress Jitō (645-702)
• Empress Gemmei (661-721)
• Empress Genshō (680-748)
• Empress Kōken (718-770)
• Empress Shōtoku (718-770)
• Empress Meishō (1624-1696)
• Empress Go-Sakuramachi (1740-1813)

Many believe that female dictators are uncommon, even rare, when in actuality the opposite is the reality. There have been many women who have ruled their nations with absolute power. It is often just necessary to remove one's masculine predisposition to the term dictator.