How to Use Either and Neither

"Either" and "neither" are both singular adjectives meaning "one or the other of two." "Neither" of course means "not the first one and not the second one."

In formal writing, we usually use a singular verb because "either" and "neither" signal that one of the following nouns is the subject, but not both:

Either Bill or Bob is going to the conference. (One or the other is going, but not both.)
Neither Joan nor Jane likes sushi. (= Joan doesn't like sushi. Jane doesn't like sushi either!)

Notice that we say "either...or" and "neither...nor." In informal English, most people would say "Neither Joan OR Jane LIKE sushi." That's all right in conversation, but in formal documents you should prefer the formal usage.

Of course we have a confusing exception to this rule. You can use a plural verb if you have a plural noun next to the verb:
Either Joan or the Kennedys are going to the conference.

But put the singular noun closer to the verb, and it goes back to singular!
Either the Kennedys or Joan is going to the conference.

And it's the same with "neither":
Neither Jane nor her brothers like sushi.
Neither her brothers nor Jane likes sushi.

Of course the verb will be plural if both nouns are plural:
Either the Smiths or the Robinsons are meeting us at the station.
Neither the Canadians nor the Americans are interested in this problem.

Study the following formulas.

{neither/either} + noun + {nor/or} + plural noun + plural verb

Neither John nor his friends are going to the beach today.
plural noun plural verb

Either John or his friends are going to the beach today.
plural noun plural verb

{neither/either} + noun + {nor/or} + singular noun + singular verb

Neither John nor Jill is going to the beach today.
singular noun singular verb

Either John or Jill is going to the beach today.
singular noun singular verb

Examples:
Neither John nor Jane is going to class today.
singular noun singular verb

Neither Maria nor her friends are going to class today.
plural noun plural verb

John or George is bringing the car.
singular noun singular verb

Neither the boys nor Carmen has seen this movie before.
singular noun singular verb

Neither the direction nor the secretary wants to leave yet.
singular noun singular verb