Shadow chancellor John McDonnell joined lecturers on the picket line at Goldsmiths, which is one of 16 London institutions who have gone on strike.
The dispute is over pensions which the University and College Union say will leave teaching staff almost £10,000 a year out of pocket.
The strikes will affect around 180,000 students in the capital.
A London student, Rachel Maguire, has started a petition calling for compensation for those affected by the strikes at Birckbeck College.
The industrial action comes after changes were announced to the pension scheme for Birkbeck staff.
The union estimates that over half a million teaching hours will be lost during the four-week strike programme.