“Disappointed in” versus “disappointed with”

Question

I'm aware there are different prepositions possible after disappointed: with, in, of, at. I'm particulary interested in the difference between with and in.

• I'm disappointed with you.
• I'm disappointed in you.

Which one is correct? Or do they have a slightly different meaning?

Answer 1

I don't know about any official documentation on this, but it seems from usage that "disappointed with" typically precedes a demonstrative pronoun, while "disappointed in" directly precedes a subject or an article and subject:

I'm disappointed in the ruling.
I'm disappointed in Tom.

I'm disappointed with that result.
I'm disappointed with her performance.

The 'that' and 'her' are demonstrative pronouns, while 'Tom' and 'the ruling' are subjects ('the' obviously being the article).

Answer 2

While both prepositions are correct for everything, I would tend to use disappointed in for people and disappointed with for objects or events. I'm not alone. Consider the following Google Ngram

The majority of the time, the noun following the will not be a person, whereas you always refers to a person.

Answer 3

To me there is no difference between the two. I can imagine a situation where my boss comes to me and says either of the sentences above. I wouldn't walk away with any different an interpretation It seems as though the words "with" and "in" have lost their semantic role and serve only as markers that carry the significance of "dissapointed" to the object.

In regards to "of" and "at," "of" seems to be poor usage with a confusing meaning and "at" tends to get the message across but in a less clear and colloquially inefficient manner.

Answer 4

disappointed: upset because sth you hoped for has not happened or been as good, successful, etc. as you expected. Examples: - They were bitterly disappointed at the result of the game. - I was disappointed by the quality of the wine. - I’m disappointed in you—I really thought I could trust you! - I was very disappointed with myself.
- He was disappointed to see she wasn’t at the party. - I’m disappointed (that) it was sold out. - She was disappointed not to be chosen.

As you can see, there are many options to choose from. It´s a matter of context which preposition you have to choose.

In your case:

"I am dissapointed in you." and "I am dissapointed with you." are both correct, while "I am dissapointed at you." is incorrect and "I am dissapointed by you." sounds awkward to me. It would be better an expression such as "I am disappointed by (or with) your behavior."