Christine Fair was suspended from Larkhall Academy in Lanarkshire after claims she had sex with a male pupil in 2009.
She was also accused of buying alcohol for pupils in Airth, Falkirk, during a school prom.
Yesterday a disciplinary hearing of the General Teaching Council for Scotland found both charges against Ms Fair proven.
The committee also decided to refer her to the Scottish Government for possible inclusion on a list of individuals who are not allowed to work with children.
Although the pupil involved did not appear before the hearing, the committee said it had enough evidence to "fulfil its duty under the Teaching (Scotland) Act" in striking Ms Fair off the teaching register.
A spokesman for South Lanarkshire Council said: "We can confirm that Christine Fair left the employment of the council in 2009."