How to use olvidar/olvidarse for "to forget" (pronominal verbs/accidental se)

In Spanish there are different ways to express "to forget". The verb olvidar can be used as well as its reflexive form, olvidarse.

Let's see some examples:

He olvidado las llaves.I forgot the keys.

Me he olvidado de las llaves.I forgot the keys.

As you can see, in the first example we use "olvidar [algo]" and in the second example we use "olvidarse" [de algo]". 

There is no difference in meaning. Using one or the other depends on what the person is used to; some regions in Spain use one form more than the other, but both are correct.

It is important to remember that when using the reflexive form olvidarse, that it needs the preposition "de" before the direct object. It would be incorrect to omit it: "Me he olvidado las llaves."

With the verb olvidar, we can express that we

  • forget something
  • forget to do something
  • forget about doing something

For example:

Laura ha olvidado la cita.Laura forgot [about] the appointment.

Laura ha olvidado ir a la cita.Laura forgot to go to the appointment.

Laura ha olvidado que tenía una cita.Laura forgot that she had an appointment.

The accidental "se" with olvidarse

Another way of using the verb olvidar is with the "accidental se". Have a look:

Se me han olvidado las llaves.I forgot the keys. (The keys were forgotten by me)

If we analyse the structure of this sentence you can see that the subject is "what is forgotten", in this case, the keys.

The verb is conjugated in the third person plural "han olvidado" to agree with the subject which is "the keys las llaves".

There is an indirect pronoun "me" to say who forgot the keys. It is as if we were saying "The keys were forgotten to me.".

If we mention the person, we need to add "a +person", the same way we do with the verb gustar. For example:

A mí se me han olvidado las llaves.I forgot the keys.

A Elena se le han olvidado las llaves.Elena forgot the keys.

Important: here we cannot use preposition de

"Se me han olvidado de las llaves."

This structure is called "accidental se", and it is used to emphasise that something was "passively/accidentally/unintentionally done". 

Be careful when what is expressed is "someone forgets to do something". In this case, the verb will always be conjugated in the 3rd person singular, not plural, independently of what comes after. The infinitive is taken as the subject of the sentence and it will be considered as a singular subject. 

For example:

A Juan se le olvidó traer el hielo.Juan forgot to bring the ice.

A Juan se le olvidó traer cervezas.Juan [accidentally] forgot to bring beers.

In the second example there is the plural word "cervezas" but the verb "olvidarse" is still conjugated in the 3rd person singular, not plural, to agree with the infinitive.

Remember that the order in this structure is:

se + indirect object pronoun + verb + object

See also Conjugate recordar, acordar and acordarse o > ue stem changing -ar verbs in El Presente (present tense)  and Using the "accidental" reflexive (se) with an indirect object pronoun  

 

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Examples and resources

Me he olvidado de las llaves.I forgot the keys.
¡Se nos olvidó la crema solar!We forgot the sun-cream!
Siempre se me olvida la botella de agua cuando voy al gimnasio.I always forget the water bottle when I go to the gym.
A Elena se le han olvidado las llaves.Elena forgot the keys.
He olvidado las llaves.I forgot the keys.
¡Nos olvidamos de la crema solar!We forgot the sun-cream!
Siempre me olvido de la botella de agua cuando voy al gimasio.I always forget the water bottle when I go to the gym.
A mí se me han olvidado las llaves.I forgot the keys.
A Juan se le olvidó traer cervezas.Juan [accidentally] forgot to bring beers.
A Juan se le olvidó traer el hielo.Juan forgot to bring the ice.
Siempre olvido la botella de agua cuando voy al gimasio.I always forget the water bottle when I go to the gym.
Laura ha olvidado que tenía una cita.Laura forgot that she had an appointment.
Juan se olvidó de traer el hielo.Juan forgot to bring the ice.
¡Olvidamos la crema solar!We forgot the suncream!
Se me han olvidado las llaves.I forgot the keys. (The keys were forgotten by me)
Laura ha olvidado ir a la cita.Laura forgot to go to the appointment.
Juan olvidó traer el hielo.Juan forgot to bring the ice.
Laura ha olvidado la cita.Laura forgot [about] the appointment.
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