The pluperfect (shortening of plusquamperfect), usually called past perfect in English, characterizes certain verb forms and grammatical tenses involving an action from an antecedent point in time. Examples in English are: "we had arrived" before the game began; "they had been writing" when the bell rang.

The word derives from the Latin plus quam perfectum, "more than perfect". The word "perfect" in this sense means "completed"; it contrasts with the "imperfect", which denotes uncompleted actions or states.

In English grammar, the pluperfect (e.g. "had written") is now usually called the past perfect, since it combines past tense with perfect aspect. (The same term is sometimes used in relation to the grammar of other languages.) English also has a past perfect progressive (or past perfect continuous) form: "had been writing".

The pluperfect is traditionally described as a tense; in modern linguistic terminology it may be said to combine tense with grammatical aspect; namely past tense (reference to past time) and perfect aspect. It is used to refer to an occurrence that at a past time had already been started (but not necessarily completed), (e.g. "It had already been raining for a week when the big storm started.").

Bernard Comrie classifies the pluperfect as an absolute-relative tense, because it absolutely (not by context) establishes a deixis (the past event) and places the action relative to the deixis (before it).

Examples of the English pluperfect (past perfect) are found in the following sentence (from Viktor Frankl's Man's Search for Meaning):

A man who for years had thought he had reached the absolute limit of all possible suffering now found that suffering had no limits, and that he could suffer still more, and more intensely.

Here, "had thought" and "had reached" are examples of the pluperfect. They refer to an event (a man thinking he has reached the limit of his capacity to suffer), which takes place before another event (the man finding that his capacity to suffer has no limit), that is itself a past event, referred to using the past tense (found). The pluperfect is needed to make it clear that the first event (the thinking and the supposed reaching) is placed even earlier in the past.