Yes, but non-British subjects cannot use the title 'Sir' if knighted. An example is Bill Gates; he has been knighted and can use the initials KBE (Knight of the British Empire) after his name, but he cannot call himself Sir Bill Gates.
So, can a woman be knighted?
For recognised meritorious service to the community a woman is awarded a damehood, which accords her the same kudos, not to mention security and freedom as a knighthood gives a knight, so she could be said to be delighted in place of knighted! The male equivalent to a dame is a major domo.
Can an Irish person get a knighthood?
CAN NON-BRITISH CITIZENS BE KNIGHTED? Sort of. In 2005, Irish-born BBC personality Terry Wogan received an honorary knighthood, and when he became a British citizen later that year, he could start making people call him Sir Terry Wogan.
Can an Australian be knighted by the Queen?
Unlike other foreign citizens, citizens of Commonwealth realms appointed knight or dame of a British order are entitled to use the titles "Sir" or "Dame", and use the relevant post nominal. The UK government does not recognize Australian knighthoods as giving entitlement to use these titles in the UK, however.