The Verb 'lassen' (Let / Have Done)

Lassen is one of German’s most versatile verbs, acting both as an independent main verb (to leave) and as a semi-modal verb paired with an infinitive (to let, to have something done, or can be done). Because English expresses those four ideas with different verbs, mastering lassen unlocks a huge range of everyday and B2-level phrasing.

Irregular Conjugation of lassen

Like strong verbs with an a → ä stem vowel change, lassen changes its vowel in the du and er/sie/es present tense forms, drops the extra s in du lässt, and takes a strong ie stem in the simple past (Präteritum).

Notice the two Perfekt options in the bottom row: the standalone verb uses gelassen, while semi-modal uses with another verb trigger the double infinitive construction.

The 4 Core Meanings of lassen

1. To Leave Something Somewhere (Standalone Main Verb)

When lassen has no second verb, it means leaving a person or object in a place or state:

• Ich habe mein Handy (das Handy) zu Hause gelassen. (I left my phone at home.)
• Lass mich in Ruhe (die Ruhe)! (Leave me alone / in peace!)
• Er hat den Schlüssel (der Schlüssel) auf dem Tisch (der Tisch) gelassen. (He left the key on the table.)

2. To Let or Allow Someone to Do Something

Paired with a bare infinitive (never zu), lassen means granting permission or not interfering—just like modal verbs:

• Lass mich erklären. (Let me explain.)
• Er lässt die Kinder (Pl., das Kind) im Garten (der Garten) spielen. (He lets the children play in the garden.)
• Die Lehrerin (die Lehrerin) lässt die Klasse (die Klasse) früher gehen. (The teacher lets the class leave early.)

Notice that the person allowed to act (mich, die Kinder, die Klasse) is in the accusative whenever there is no other accusative object.

3. Causative: To Have Something Done

When you arrange for someone else to perform a service—like cutting hair, repairing a car, or renovating a house—German uses lassen + infinitive, typically leaving out the person who does the actual work:

• Ich lasse mir die Haare (Pl., das Haar) schneiden. (I’m having my hair cut.)
• Er lässt das Auto (das Auto) reparieren. (He’s having the car repaired.)
• Wir haben das Haus (das Haus) renovieren lassen. (We had the house renovated.)

Watch the case of the person in causative phrases: if an accusative object (die Haare, einen Anzug) is already named, the person benefiting from the action stands in the dative (Ich lasse mir die Haare schneiden; Sie lässt sich ein Kleid (das Kleid) nähen).

4. sich lassen + Infinitive (Passive Substitute)

When combined with the reflexive pronoun sich and an inanimate subject, sich lassen + infinitive becomes a natural passive substitute expressing possibility (can be done / cannot be done):

• Das lässt sich machen. (That can be done. / That’s doable.)
• Das Fenster (das Fenster) lässt sich nicht öffnen. (The window won’t open / cannot be opened.)
• Dieses Problem (das Problem) lässt sich schnell lösen. (This problem can be solved quickly.)

In every example above, sich lassen replaces können + passive (Das Fenster kann nicht geöffnet werden) with cleaner, more idiomatic German.

The Double Infinitive in the Perfekt and Subordinate Clauses

Whenever lassen acts as a semi-modal alongside a dependent infinitive (meanings 2, 3, and 4), German replaces the participle gelassen with the infinitive lassen, creating a double infinitive at the end of the clause:

• Sie hat die Kinder spielen lassen. (She let the children play. — NOT spielen gelassen)
• Er hat sich die Haare schneiden lassen. (He had his hair cut.)
• Das Problem hat sich nicht lösen lassen. (The problem could not be solved.)

If the clause is a subordinating conjunction clause (weil, dass, obwohl), the conjugated auxiliary haben jumps in front of the double infinitive rather than sitting at the very end:

• …, weil wir das Haus haben renovieren lassen. (… because we had the house renovated.)

Common Mistakes to Avoid