Few Dutch policies get described as inconsistently as this one, with confident answers landing on both yes and no. Both are partly right: the default rule and the list of exceptions point in opposite directions, and a large share of new Dutch citizens land inside the exceptions.
Officially, no — the default under Dutch nationality law (Rijkswet op het Nederlanderschap) is that you renounce your other nationality when you naturalise, and the same applies in reverse if you're already Dutch and voluntarily pick up another nationality as an adult. But the exceptions are broad enough that a huge share of new Dutch citizens end up dual anyway: your home country's law makes renouncing legally impossible (Iran is the classic example) or strips it automatically regardless (Suriname, China); you're married to or registered-partnered with a Dutch citizen; you're a recognised refugee; you were born in the Kingdom and still live there; or you fall under a discretionary "reasonable grounds" category IND assesses case by case, like disproportionate financial cost or losing inheritance rights back home. There's a long-pending bill from D66 and GroenLinks-PvdA that would flip the default entirely, letting Dutch citizens keep their nationality when acquiring another, and it's been quietly moving through parliament — but as of August 2026 it still hasn't had its final vote. Check ind.nl's dual-nationality page for the current exception categories before assuming yours applies.