The TIE Fighter, a fictional starfighter in the Star Wars universe, is the standard Imperial starfighter. They are seen in massive numbers throughout the main trilogy. While manoeuvrable, they have no shields and many of their pilots are poorly trained and thus easy targets for the Rebel Alliance X-wing and A-wing fighters. They are armed with twin laser cannons. They do not carry missile tubes in standard configurations, but these can be added on if necessary.
In the X-Wing/TIE Fighter computer game series, the TIE Fighter is not equipped with rechargable shields possessed by rebel craft and other Imperial fighters. While dangerous in large numbers, one on one they are easy pickings for other craft to the point where few scenarios in the games call for a player-controlled TIE Fighter to go up against modern Rebel craft.
TIE stands for "Twin Ion Engine".