Does the Dutch pay transparency law apply to a foreign employer?

Yes, presumably so — if your staff works in the Netherlands

For a foreign employer with staff in the Netherlands, the employer's place of establishment does not apply, but rather where the employment relationship takes place. Article 2 of Directive (EU) 2023/970 describes the scope as employers in the public and private sectors, without imposing any nationality or establishment requirement on the employer itself. This suggests that an organization established in another country but employing staff who work in the Netherlands will face the Dutch implementation of the directive for that staff once it comes into force — in the same way as a Dutch employer.

At present, this changes little in practice. The Dutch legislative proposal (36949) is still under consideration by the House of Representatives, and the obligations it contains do not yet apply to private employers, regardless of which country they are established in. For employers in the public and semi-public sectors, it is different: because the implementation deadline for the directive has now passed, they may already be directly bound by the directive provisions for staff working in the Netherlands, even if the organization itself is established elsewhere. Those in that category who still need to begin with an objective job classification may therefore have less time than the target date of the law suggests.

Source: the scope in Article 2 and the status of legislative proposal 36949

The fact that the place of work is decisive and not the establishment of the employer follows from the broad, location-independent wording of Article 2 of Directive (EU) 2023/970. The fact that the obligations for private employers in the Netherlands do not yet apply, and may already have direct effect for public and semi-public employers, follows from the legislative status of proposal 36949: it has been submitted but not yet adopted, while the implementation deadline for the directive has already passed.