The middle voice is one of the most distinctive features of Icelandic and one English lacks entirely. You form it by attaching the suffix -st to a verb — opna "open" → opnast "open (by itself)", hitta "meet" → hittast "meet each other" — and the result is a verb with a new, often quite different meaning. Crucially, the middle voice is not simply a way of making things passive. It is a productive voice that covers several distinct jobs: making a verb reflexive, making it reciprocal, making it describe something happening on its own, and — very often — creating an idiosyncratic, lexicalised verb whose meaning you could never guess from the base. Because of that last point, the single best mindset is to treat -st verbs as their own words. This page orients you to the four meaning-types; the mechanics of building the forms, and the special experiencer verb finnast, have their own pages.
What the -st suffix is and where it sits
Historically, -st comes from a fused reflexive pronoun sik ("oneself") that attached to the verb and wore down over the centuries. That origin explains why the middle voice so often has a "to/at oneself" flavour. Mechanically, -st attaches after the personal ending, at the very end of the conjugated form: ég opna → ég opnast, hann opnar → hann opnast. In the preterite of weak verbs a linking -ði- or -i- appears before -st: opna → past opnaðist, hitta → past hittist. (The full form-building rules are on the Middle Voice Forms page.)
The four meaning-types
The same suffix produces four recognisable kinds of meaning. Knowing the menu lets you interpret an unfamiliar -st verb sensibly — and reminds you that you often still have to look it up.
| Type | Base → middle | Meaning of the -st verb |
|---|---|---|
| Reflexive | klæða "dress (s.o.)" → klæðast | dress oneself / wear |
| Reciprocal | sjá "see" → sjást | see each other / be visible |
| Anticausative | opna "open (s.t.)" → opnast | open by itself |
| Lexicalised | finna "find" → finnast | seem / find (be of the opinion) |
1. Reflexive: the action turns back on the subject
When the subject does the action to itself, the middle voice packages "myself / yourself" into the verb. Klæðast is "to dress oneself / to wear"; you don't add a separate reflexive pronoun. This is the meaning that most directly reflects the sik origin.
Hún klæðist alltaf svörtu á sviðinu.
She always dresses in / wears black on stage. (klæðast = 'dress oneself', + dative of what's worn)
2. Reciprocal: the subjects act on each other
With a plural subject, the middle voice often means the people do the action to one another. Hittast is "meet each other", sjást "see each other" (and, by extension, "be visible/show"), kyssast "kiss each other". English needs a separate "each other"; Icelandic folds it into -st.
Við hittumst fyrir utan bíóið klukkan sjö.
Let's meet (each other) outside the cinema at seven. (hittast = reciprocal 'meet')
Fjöllin sjást varla í þokunni.
The mountains are barely visible in the fog. (sjást — here the 'be visible' sense)
3. Anticausative: it happens by itself
A transitive verb with an outside cause ("someone opens the door") becomes, in the middle, an event that happens on its own, with no agent in view: opna "open (something)" → opnast "open (by itself)". This is the type closest to a passive, which is exactly why learners confuse the two — but the difference is real: the anticausative says the event simply happened, not that some unstated person did it.
Hurðin opnaðist hægt af sjálfu sér.
The door opened slowly by itself. (opnast — anticausative; past opnaðist)
Glasið brotnaði þegar það datt.
The glass broke when it fell. (brotna(st)-type 'break by itself', no agent)
4. Lexicalised: a meaning you cannot predict
This is the largest and most important class. Very often the -st verb has drifted into a meaning that has no transparent connection to the base, so it lives in the dictionary as its own word. Finnast looks like finna "find", but means "to seem / to be of the opinion" (with a dative experiencer): mér finnst "it seems to me / I think". Komast is built on koma "come" but means "manage to get (somewhere)". You simply have to learn these as independent lexemes.
Mér finnst þetta frábær hugmynd.
I think this is a great idea. / This seems great to me. (finnast = 'seem/think', dative mér)
Við komumst loksins heim eftir miðnætti.
We finally managed to get home after midnight. (komast = 'manage to get', not just 'come')
The headline for this type — and for the whole page — is that you cannot reliably derive the meaning of an -st verb from its base verb. Finnast is not "find oneself"; komast is not "come oneself". Treat each one as vocabulary.
Middle voice vs the periphrastic passive
Because the anticausative type looks passive, English speakers are tempted to use -st whenever they would use the English passive ("the door was opened", "the book was read"). Resist this. Icelandic has a separate, dedicated passive built with vera "be" plus the past participle (hurðin var opnuð "the door was opened [by someone]"), and that is the construction for a true passive with an implied agent. The middle opnast specifically means it opened by itself, agent-less by nature. Use the periphrastic passive when there is an unstated doer; use the middle when the event genuinely happens on its own. The passive has its own page.
Hurðin var opnuð af dyraverðinum.
The door was opened by the doorman. (true passive — vera + participle, agent present)
Hurðin opnaðist af sjálfu sér.
The door opened by itself. (middle voice — no agent)
A note on productivity
The middle voice is productive: Icelandic speakers can and do form new -st verbs, and many ordinary verbs have a live middle form alongside their plain form. But productivity does not mean predictability of meaning. Some -st forms are regular anticausatives; many are lexicalised. The practical upshot is the same advice once more: when you meet an -st verb, check what it actually means rather than assuming it is "the passive of X".
Þau kysstust á brúnni í rigningunni.
They kissed (each other) on the bridge in the rain. (kyssast — reciprocal; past kysstust)
Common Mistakes
❌ Bókin lasst af mörgum.
Incorrect — to say 'the book was read by many', use the periphrastic passive, not -st.
✅ Bókin var lesin af mörgum.
The book was read by many. (true passive: vera + participle)
The middle voice is not a general passive. When there is an agent (even an implied one), use vera + past participle.
❌ Mér finn að þetta sé gott.
Incorrect — 'I think/it seems to me' is the lexicalised middle finnast, not finna.
✅ Mér finnst að þetta sé gott.
It seems to me / I think this is good.
Finna "find" and finnast "seem/think" are different verbs. The opinion sense is the -st form, with a dative experiencer (mér finnst).
❌ Ég komaði heim seint.
Incorrect — 'I managed to get home' is komast (past komst), not a plain past of koma.
✅ Ég komst heim seint.
I managed to get home late.
Komast "manage to get" is a lexicalised middle with its own forms; don't try to build it as a regular past of koma.
❌ Ég klæði svörtu í dag.
Incorrect — 'I'm wearing black / dressing in black' is the reflexive middle klæðast.
✅ Ég klæðist svörtu í dag.
I'm wearing black today.
To dress oneself (rather than dressing someone else), use the middle klæðast — with the dative of what you wear.
❌ Við hittum klukkan sjö.
Incorrect for 'we'll meet (each other)' — that reciprocal sense needs hittast.
✅ Við hittumst klukkan sjö.
We'll meet at seven.
Hitta means "meet (someone)"; for "meet each other" you need the reciprocal middle hittast.
Key Takeaways
- The middle voice is formed with the suffix -st, which attaches after the personal ending (opna → opnast); the weak preterite inserts -ði-/-i- before it (opnaðist, hittist).
- It descends from the reflexive sik "oneself", which is why it yields reflexive (klæðast), reciprocal (hittast, sjást), and anticausative / "by itself" (opnast) meanings.
- A large class is lexicalised — finnast "seem/think", komast "manage to get" — with meanings you cannot predict from the base; learn -st verbs as their own lexemes.
- The middle is not the passive: a true passive uses vera
- past participle (var opnuð). The middle opnast means it opened by itself.
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Start learning Icelandic→Related Topics
- Conjugating Middle-Voice VerbsB1 — How to build the forms of -st (middle-voice) verbs across the whole paradigm: the present in which 2sg and 3sg merge because -st swallows the personal -r, the often-bare 1sg, the preterite that stacks a dental + -st (settist, klæddist, komst), and the supine in -st — drilled on the weak verb setjast and the strong verb komast.
- Reciprocal and Anticausative -stB2 — The two most productive jobs of the -st middle voice: the reciprocal ('each other' — hittast, sjást, kyssast, berjast) and the anticausative ('happen by itself' — opnast, lokast, breytast). How the reciprocal folds in English 'each other' and the anticausative detransitivises a verb, plus why the anticausative is Icelandic's natural alternative to a passive for events with no agent.
- The Passive Voice: vera/verða + ParticipleB1 — Icelandic's periphrastic passive built from vera 'be' (a stative result) or verða 'become' (a dynamic event) plus a past participle that AGREES with the subject in gender, number, and case — bréfið er skrifað vs bréfið verður skrifað — and why one English passive splits into three Icelandic strategies.
- finnast vs þykja vs halda: 'Think/Seem'B1 — The 'think/seem/find' cluster that English collapses into one word: finnast (dative subject, a subjective impression — mér finnst þetta gott), þykja (dative subject, more formal and evaluative — mér þykir vænt um þig), and halda (ordinary nominative subject, a belief or conjecture — ég held að…). The case of the subject is the giveaway: an impression takes mér; a belief takes ég.
- Reflexive Verbs and Inherent ReflexivesB2 — Verbs used with the reflexive pronoun sig/sér/sín. True reflexives (hann þvær sér 'he washes himself') where the reflexive is a real object, versus inherently reflexive verbs (flýta sér, skemmta sér, ná sér) where the reflexive is obligatory and carries no separate meaning. Some require dative sér (flýta sér), some accusative sig (hreyfa sig). Plus the benefactive dative reflexive — fá sér, kaupa sér — that marks an action as 'for one's own benefit'. Crucially, sig/sér/sín is 3rd person ONLY; for 'we hurry' you say flýtum okkur.
- finnast (to think / seem — opinion verb)A2 — Full conjugation of finnast, the everyday opinion verb with a DATIVE subject (mér finnst þetta gott), its quirky-subject syntax, plural agreement with the nominative theme (mér finnast þau góð), the past fannst, and how it differs from halda and líka.