In a country where the name itself is ambiguous, it's hard to say where the capital sits.
Amsterdam is the "hoofdstad" the head city.
But The Hague (Den Haag) has since 1584 been the regeringszetel the seat of government. The parliament, the cabinet of ministers, the monarch, and almost all ambassadors are housed there.
Amsterdam is amongst only a few cities worldwide that are officially the capital but which do not seat the national government.