Overview of Relative Pronouns:

Relative pronouns identify nouns that have previously been used in a sentence and provide information about that noun ("who(m)", "which", "what" and "that" in English), e.g.: El hombre a quien conocí se llama Richard. "The man whom I met is called Richard." Here we see that the relative pronoun quien is used to make a link between a noun (El hombre) and information about the noun (a quien conocí).

Let's look at the relative pronouns used in Spanish:

Que

Que is used directly after a noun, regardless of whether the noun is a person or thing. It translates to English "what", "who(m)","which" or "that", e.g.:

• La niña que estudia historia es de Chile. "The girl that studies history is from Chile."
• La persona que vi es estudiante. "The person whom I saw is a student."

Que can also appear as part of a prepositional group, e.g.: a que, de que, con que, en que (NOT sin que "without", porque "because" or para que "so that/in order that"), e.g.: 

• El socialismo es el tema de que va a hablar el profesor. "Socialism is the theme about which the professor is going to talk."

When preceded by a preposition, the noun referred to is non-animate (i.e.: not a person).

Que is also found with determiners: el que, la que, los que, las que. The articles must agree in gender and number with the noun they refer back to. These relative pronouns are set off by punctuation or separated (by prepositions) from the noun they refer to. They are always used with the prepositions sin, por and para in order to avoid confusion with the conjunctions sin que, porque and para que, e.g.:

•  Esta niña, la que está llorando, no quiere comer sus verduras. "The little girl, the one that is crying, doesn't want to eat her vegetables."
• Necesitamos sacar los pasaportes sin los que no podemos viajar. "We need to get our passports without which we can't travel."

Que is not always a relative pronoun and can also function as a conjunction where it simply joins two clauses, e.g.:

• Yo veo que tú vienes. "I see that you are coming."

Quien(es)

This relative pronoun is used to refer back to a person that has been previously mentioned and agrees with that noun in number. The relative pronoun and the person referred to must be separated by either a comma or a preposition (de quien, a quien, por/para quien). If the noun and the relative pronoun are not separated, you must use que, not quien(es).

• Mi amiga Sara, a quien le di el libro, no sabe mucho de la historia. "My friend Sara, to whom I gave the book, doesn't know much about history."
• El doctor, quien no habla español, va a hacer la operación. "The doctor, who doesn't speak Spanish, is going to do the operation."
• Los niños, para quienes construyeron la nueva escuela, empiezan sus estudios mañana. "The children, for whom they built the new school, begin their studies tomorrow."

El/la/los/las cual(es)

These relative pronoun means "(that/those) which" or "that" and is used when there is more separation between the relative pronoun and the noun it refers to. Relative pronouns using cual that are set off by commas are used to specify the noun you are referring to from a group. These relative pronouns also commonly occur with phrasal prepositions that create distance between the noun and relative pronoun, such as acerca de, después de, antes de, etc. The article in front of cual must agree in gender and number with the noun it refers to, creating multiple forms of this pronoun: el cual, la cual, los cuales, and las cuales, e.g.:

• No nos gustan las películas de horror en las cuales hay asesinatos porque nos dan miedo. "The horror movies, (the ones) which are about murders, scare us."
• Vamos al concierto de rock, después del cual vamos a la fiesta de Carolina. "Let's go to the concert, after which we'll go to Carolina's party."

Lo que

This is used to refer to a general noun that is an idea, event or abstract concept (i.e.: not a specific feminine or masculine noun) and can mean "that", "what" or "that which". If you would use "what" to start a sentence in English, use lo que in Spanish. Lo que does not have to refer to a noun that has been previously mentioned, unlike other relative pronouns, e.g.:

• Lo que vamos a hacer es ir a la oficina del executivo para hablar con él. "What we are going to do is go to the executive's office to speak with him."
• Saqué una nota muy baja, lo que me hizo triste. "I got a very low grade, which made me sad."

Cuando

Th relative pronoun cuando means "when" and is used to refer back to an event, e.g.:

• ¿No te acuerdas cuando fuimos al restaurante en el centro? "Do you remember when we went to the restaurant en the center?"

Donde

The relative pronoun donde means "where" and is used to refer to a location, e.g.:

• El pueblo donde nació mi padre está al norte del país. "The town where my father was born is to the north of the country."

Tricky Stuff

• In English, relative pronouns can often be omitted entirely, e.g.: "The man (that) I met is your brother." This is NOT possible in Spanish, the relative pronouns must be present, e.g.: El hombre a quien conocí es tu hermano. NOT El hombre conocí es tu hermano.
• Remember that you must use the relative pronoun que if there is no separation between the noun and the relative pronoun. Even if the noun is a person do not use quien(es) if there is no separation.
• Remember that in Spanish the same words used as relative pronouns are also used as question/exclamatory words. When they are used in questions or exclamations they appear with an accent: qué, quién(es), cuál(es), dónde, cuándo.

Questions