πιστεύω (to believe) | Greek Grammar

πιστεύω is the verb you use when you are prepared to stand behind the claim. It covers believe, trust and have faith in — three English verbs, one Greek one — and the choice between them is made not by the verb but by which preposition, if any, follows it.

Principal parts

Slot	Form	Note
Present	πιστεύω, πιστεύεις, πιστεύει, πιστεύουμε, πιστεύετε, πιστεύουν(ε)
Imperfect	πίστευα
Aorist	πίστεψα, πίστεψες, πίστεψε, πιστέψαμε, πιστέψατε, πίστεψαν	no ε- augment — three syllables already carry the stress
Dependent (θα, να)	πιστέψω
Imperative	πίστευε (imperfective) · πίστεψε / πιστέψτε(perfective)	with a clitic: Πίστεψέ με
Perfect / pluperfect	έχω / είχα πιστέψει
Gerund	πιστεύοντας
Passive	πιστεύομαι, aorist πιστεύτηκα	third person in practice: Δεν πιστεύτηκε.
-μένος participle	does not exist — but the verbal adjective πιστευτός "believable" is live, and its negative απίστευτος "unbelievable" is everyday
×πίστευσα	does not exist — the -εύω verbs form their perfective in -εψ-

Why -εύω comes out as -εψ- is worked through on aorist consonant merges; here it is enough to store πίστεψα / να πιστέψω as the perfective half, and to note that the stress slides right when the word grows: πίστεψα, but πιστέψαμε.

Στην αρχή δεν το πίστεψα, μου φάνηκε αδύνατο.

stin archí dhen to pístepsa, mu fánike adhínato

I didn't believe it at first — it seemed impossible to me.

Το πιστέψαμε όλοι και στο τέλος μας κορόιδεψε.

to pistépsame óli ke sto télos mas koróidhepse

We all fell for it, and in the end he had us on.

Ήταν απίστευτο αυτό που έγινε στο τελευταίο λεπτό.

ítan apístefto aftó pu éyine sto teleftéo leptó

What happened in the last minute was unbelievable.

Government

Frame	Example	Claim being made
bare accusative	Σε πιστεύω.	I believe what you are telling me
σε accusative	Πιστεύω σε σένα.	I have faith in you — in God, in an idea
ότι / πως indicative	Πιστεύω ότι θα βρεθεί λύση.	I hold this to be true
να verb	Πιστεύω να πέρασες καλά.	expectation, not belief — "I trust / I hope"

The first two rows are the pair learners fuse, and they fuse them because the two σε's are not the same word. In σε πιστεύω it is the weak accusative pronoun "you"; in πιστεύω σε σένα it is the preposition, with σένα as its object. One accepts a statement, the other commits to a person. Where each frame comes from is the wider subject of verb government with prepositions.

Σε πιστεύω, αλλά τα νούμερα λένε κάτι άλλο.

se pistévo, alá ta númera léne káti álo

I believe you — but the figures say something else.

Πιστεύω σε σένα, ακόμα κι αν δεν πιστεύεις εσύ.

pistévo se séna, akóma ki an dhen pistévis esí

I have faith in you, even if you don't.

Δεν πιστεύω στα ζώδια, αλλά τα διαβάζω κάθε πρωί.

dhen pistévo sta zódhia, alá ta dhiavázo káthe proí

I don't believe in star signs, but I read them every morning.

The fourth row is worth separating out, because it is not a variant of the third. πιστεύω ότι asserts; πιστεύω να expects — it is closer to English I trust or I hope, and it takes no ότι at all. The general division of labour between ότι, πως and να belongs to the complementizers; what is specific to this verb is that the two frames mean different things rather than the same thing twice.

Πιστεύω να πέρασες καλά στο ταξίδι, φαίνεσαι ξεκούραστος.

pistévo na pérases kalá sto taksídhi, fénese ksekúrastos

I trust you had a good time on the trip — you look rested.

How strong is the claim?

Run one proposition through the three verbs and the temperature drops each time.

Verb	Force	Same sentence
πιστεύω	conviction — I'd defend this	Πιστεύω ότι θα έρθει.
θεωρώ	reasoned judgement (formal)	Θεωρώ ότι θα έρθει.
νομίζω	a guess that may well be wrong	Νομίζω ότι θα έρθει.

💡

Do not use πιστεύω as a filler for English "I think". Πιστεύω ότι είναι στο τρίτο πάτωμα tells your listener you are sure enough to be quoted on it — for directions half-remembered, Greek reaches for νομίζω. Both sentences below are correct Greek; only one of them is honest.

Πιστεύω ότι είναι ο καλύτερος γιατρός στην πόλη.

pistévo óti íne o kalíteros yatrós stin póli

I'm convinced he's the best doctor in town.

Νομίζω ότι είναι στο τρίτο πάτωμα, αλλά ρώτα να σιγουρευτείς.

nomízo óti íne sto tríto pátoma, alá róta na sighureftís

I think it's on the third floor, but ask to make sure.

Set phrases

Phrase	Meaning
Δεν το πιστεύω!	I don't believe it! — surprise, not doubt
δεν πιστεύω στα μάτια μου	I can't believe my eyes
θέλω να πιστεύω ότι…	I'd like to think that… — hope with a reservation
Πίστεψέ με	believe me, take it from me
Ποιος να το πίστευε;	who'd have thought it?
το Πιστεύω	the Creed — a noun made from the verb's own 1st person singular

Δεν το πιστεύω! Πότε προλάβατε να τα βάψετε όλα;

dhen to pistévo! póte prolávate na ta vápsete óla;

I don't believe it! When did you find time to paint the lot?

Πίστεψέ με, δεν άξιζε τον κόπο να πάμε τόσο μακριά.

pístepsé me, dhen áksize ton kópo na páme tóso makriá

Take it from me, it wasn't worth going that far.

Common Mistakes

Keeping σε in front of a clause. Learners who store the verb as "πιστεύω σε" carry the preposition into the ότι-clause, where nothing can stand between the verb and its complementizer.

❌ Πιστεύω σε ότι θα τα καταφέρεις μόνος σου.

Incorrect — σε introduces a noun, not a clause. Before ότι the verb stands bare: Πιστεύω ότι…

✅ Πιστεύω ότι θα τα καταφέρεις και χωρίς εμένα.

pistévo óti tha ta kataféris ke chorís eména

I believe you'll manage even without me.

Key Takeaways

The whole verb: πιστεύω · πίστευα · πίστεψα · να πιστέψω · πίστεψε · έχω πιστέψει · πιστεύοντας.
The perfective half is -εψ-: πίστεψα, πιστέψω, and the stress moves in πιστέψαμε.
σε πιστεύω = I believe your statement; πιστεύω σε σένα = I have faith in you. The two σε's are different words — a pronoun and a preposition.
πιστεύω ότι asserts a belief; πιστεύω να expects an outcome — Πιστεύω να πέρασες καλά is "I trust you enjoyed it".
No -μένος participle, but πιστευτός and above all απίστευτος are ordinary words.
πιστεύω is conviction, not a hedge. For "I think, but don't quote me", use νομίζω.

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