Neither / neither of means not the one nor the other of two people or things.
When 'neither' is used as an adjective or pronoun it takes a singular verb.
Neither teacher is present.
When we use 'neither of' there is a bit of controversy. In speech and less formal writing a plural verb is often used,
Neither of the teachers were in the classroom.
However, purists will insist on using singular verbs.
Neither of the teachers was in the classroom.
See also neither nor vs either or
For Andrew and May