Relative pronouns die and dat: the man who, the book that

A relative pronoun joins a describing clause to a noun, the way who and that do in English: de man die naast me woont (the man who lives next to me), het boek dat ik lees (the book that I am reading). Dutch has two everyday relative pronouns, die and dat, and the choice between them depends on the noun's gender.

Use die for a de-word and dat for a het-word. The same de/het split that gives you de man and het boek also decides the relative pronoun, so die follows de man and dat follows het boek.

1. Find the noun the clause describes (the antecedent) and check its article. De vrouw is a de-word; het huis is a het-word.
2. For a de-word, use die: de vrouw die daar werkt (the woman who works there), de fiets die ik koop (the bike that I am buying).
3. For a het-word, use dat: het huis dat te koop staat (the house that is for sale), het cadeau dat ik kreeg (the gift that I got).
4. Plurals are always de-words, so a plural noun always takes die, even when the singular is a het-word: het boek → de boeken die op tafel liggen (the books that are on the table).

The clause that starts with die or dat is a subordinate clause, so its finite verb moves to the end, just as it does after omdat or dat — see the verb-final rule for subclauses.

• De brief die gisteren aankwam, was voor jou. (The letter that arrived yesterday was for you.) The verb aankwam sits at the end of the die-clause.
• Het restaurant dat we vaak bezoeken, is dicht. (The restaurant that we often visit is closed.) Bezoeken goes last, and a comma closes the clause before the main sentence continues.
• In writing, a describing clause that only adds extra information is set off with commas: Mijn buurman, die al tachtig is, fietst nog elke dag. (My neighbour, who is already eighty, still cycles every day.)

When the relative pronoun would follow a preposition, the choice stops depending on de/het and switches to a person/thing split — wie for a person (de collega met wie ik werk), a waar-form for a thing (de stoel waarop ik zit). That case has its own forms and word order, covered in relative pronouns with a preposition.

English speakers tend to choose the relative word by meaning — who for a person, which or that for a thing. Dutch ignores that and looks only at gender: die for every de-word (person or thing), dat for every het-word. So it is de tafel die (a thing, still die, because tafel is a de-word) but het meisje dat (a person, yet dat, because meisje is a het-word).