I'm a Dutch citizen with a passport and also an Iranian citizen. I would like to visit the USA. I have not been in iran for 5 years. Can I enter the USA?
In general, Dutch citizens are able to use the Visa Waiver Program (VWP) to enter the US, which would require obtaining an ESTA before travel.
However under the "Visa Waiver Program Improvement and Terrorist Travel Prevention Act of 2015", the US added additional restrictions to the VWP program, and people that are nationals of Iran, Iraq, Sudan, or Syria are no longer eligible to enter the US under the VWP - regardless of any other citizenship they hold.
If you do apply for an ESTA, you will be required to state your additional citizenship, and as a result your ESTA will be denied. Without an ESTA, you can not travel to the US using the VWP.
The only alternative that is available to you is to apply for a US Visa at a US Consulate. If a visa is approved, then you will be able to travel to the US.