Each of these words refers to that which is so small or insignificant as to be unworthy of notice or regard. Petty conveys an idea of contempt or ridicule: "Your petty complaints are really, childish." Paltry is an even stronger term, suggesting that what is beneath notice is actually to be despised: "Such a contribution from a wealthy person is paltry." That which is trivial is insignificant and even out of place in contrast to what is really important: "Your trivial comment on a great performance is silly." Related words include negligible, slight, inconsequential, inconsiderable, and trifling.
Dictionary of problem words and expressions. Harry Shaw. 1975.