Relative pronouns connect a subordinate clause to a referent and make this referent more precise. They stand directly after the noun or phrase to which they refer, and the relative clause in German is set off with commas. Form and function are linked: The pronoun agrees in gender and number with the referent, but its case depends on its role in the relative clause. This creates a clear connection between the main clause and the subordinate clause, which is also important for Subordinate clauses.

The simple relative pronouns are der, die, and das. Which form is used depends on the gender and number of the antecedent, not on the function in the relative clause. The same form can, however, take a different case in the relative clause when it is, for example, the subject, the object, or after a preposition.

IdeeIdea	BeispielExample
Maskulin Singular bestimmt derMasculine singular definite der	Der Mann, der hier wohnt.The man, who lives here.
Feminin Singular bestimmt dieFeminine singular definite die	Die Frau, die hier wohnt.The woman, who lives here.
Neutrum Singular bestimmt dasNeuter singular definite das	Das Kind, das hier wohnt.The child, who lives here.
Plural bestimmt diePlural definite die	Die Leute, die hier wohnen.The people, who live here.

In the relative clause the relative pronoun takes the case required by its function. As the subject, it is usually nominative; as the object, the accusative forms den or die; and after many prepositions the corresponding inflected form is used. This means the same referent can appear with different relative forms depending on the function expressed by the relative clause.

IdeeIdea	BeispielExample
Nominativ für das SubjektNominative for the subject	Der Lehrer, der erklärt.The teacher, who explains.
Akkusativ für das ObjektAccusative for the object	Der Lehrer, den ich kenne.The teacher, whom I know.
Dativ nach einer PräpositionDative after a preposition	Die Stadt, in der ich lebe.The city, in which I live.
Kasus richtet sich nach der FunktionCase depends on the function	Die Person, der ich helfe.The person, whom I help.

If a preposition is present in the relative clause, it belongs in front of the relative pronoun. The preposition determines the case of the form and stays tightly connected to the pronoun, as in der, with it, or for die. In fixed expressions, composite forms such as worin, worauf, or wobei can also appear, when the antecedent is indefinite or refers to a thing.

IdeeIdea	BeispielExample
Präposition steht vor dem PronomenPreposition stands before the pronoun	Das Haus, in dem wir wohnen.The house, in which we live.
Zusammengesetzte Form ersetzt Präposition und PronomenComposite form replaces preposition and pronoun	Der Platz, worauf wir sitzen.The place, on which we sit.
Wobei bezieht sich auf einen VorgangWobei refers to a process	Das Thema, wobei wir streiten.The topic, on which we argue.
In Umgangssprache erscheint oft woIn colloquial speech, wo often appears	Die Stadt, wo ich geboren bin.The city, where I was born.

For possession and belonging, the written standard uses the forms dessen and deren. Dessen refers to a masculine or neuter referent in the singular, whereas deren refers to a feminine referent or to the plural. In spoken language these forms are often replaced by dative constructions, while the genitive in the written language seems more formal.

IdeeIdea	BeispielExample
Dessen für männlich oder sächlich SingularDessen for masculine or neuter singular	Der Mann, dessen Auto vor der Tür steht.The man, whose car is parked in front of the door.
Deren für weiblichDeren for feminine	Die Frau, deren Schlüssel fehlt.The woman, whose key is missing.
Deren für PluralDeren for plural	Die Kinder, deren Eltern warten.The children, whose parents are waiting.
Schriftsprachlich und formellWritten language and formal	Der Autor, dessen Buch bekannt ist.The author, whose book is well known.

Who and what introduce free relative clauses, i.e., sentences without an explicitly named antecedent. Who is used for persons, what for things, concrete or abstract, or indefinite. These forms can bundle a general statement and prove especially useful when no single noun is in focus.

IdeeIdea	BeispielExample
Wer für PersonenWho for people	Wer hilft, wird gehört.Who helps, is heard.
Was für SachlichesWhat for things	Was du sagst, stimmt.What you say is true.
Wer allgemein auf Personen verweistWho generally refers to people	Wer früh kommt, wartet weniger.Who comes early, waits less.
Was auf Unbestimmtes verweistWhat refers to something indefinite	Was übrig bleibt, gehört dir.What remains belongs to you.

The relative clause follows directly after the antecedent so the relationship remains unambiguous. A comma separates the main clause and the relative clause, and embedding can be restrictive or add informational content. Restrictive relative clauses narrow the reference, while additive/extra information relative clauses provide additional details and are usually read as an aside in the sentence.

IdeeIdea	BeispielExample
Relativsatz folgt direktRelative clause follows directly	Der Hund, der bellt, stört mich.The dog, which barks, disturbs me.
Komma trennt den RelativsatzComma separates the relative clause	Die Tasche, die dort liegt, gehört mir.The bag, which lies there, belongs to me.
Einschränkend grenzt die Bedeutung einRestrictive narrows the meaning	Die Schüler, die lernen, bestehen.The students, who study, pass.
Zusatzinformativ gibt NebeninformationAdditive information provides supplementary details	Mein Bruder, der in Köln wohnt, kommt heute.My brother, who lives in Cologne, is coming today.

The choice of relative form depends on gender, number, and case simultaneously. The pronoun agrees with the antecedent in gender and number, but its form in the clause follows its function in the relative clause. Thus the typical combinations arise from der, die, das as well as den, dem, and the special genitive forms.

IdeeIdea	BeispielExample
Maskulin Singular mit SubjektrolleMasculine singular with subject role	derder
Maskulin Singular mit ObjektrolleMasculine singular with object role	denden
Feminin Singular mit SubjektrolleFeminine singular with subject role	diedie
Neutrum Singular mit ObjektrolleNeuter singular with object role	dasdas
Dativ nach PräpositionDative after preposition	demdem

Relative pronouns connect sentences precisely by picking up a referent and adapting in the subordinate clause to gender, number, and case. Prepositions stand before the pronoun, possessive forms such as dessen and deren appear mainly in written language, and free forms such as who and what open relative clauses without an explicitly named antecedent. Those who master these forms can form relative clauses clearly, with formal appropriateness and linguistic flexibility.