The company then intends to sue the users for defamation in New Zealand, court documents show.
Glassdoor earlier said it intended to fight to protect the identities of its users.
An order from United States Magistrate Judge Alex Tse released earlier this month shows the court has ruled in Zuru's favour.
The lengthy judgment from Tse said Glassdoor did not convince his court that the review site's interest in preserving the anonymity of its users outweighed Zuru's interest in protecting its reputation through defamation action in New Zealand.
"Because Glassdoor hasn't made that showing, and because Zuru's defamation claim is plausible, the Court will require Glassdoor to reveal who wrote the reviews," said Tse's judgment, which was first reported by journalist David Farrier.
"Zuru's defamation claim, while plausible, almost surely won't make it off the ground without Glassdoor's help.
"Glassdoor knows who wrote the reviews, Zuru doesn't. And if Glassdoor doesn't identify the reviewers, Zuru can't sue them and will be left without a means by which to 'vindicate [its] good name.'"
The Herald is seeking comment from Glassdoor on whether it will appeal.
Zuru's co-founders said their company has had to spend time and money fighting the negative publicity arising from the reviews, the judgment said.
"As an example, the co-founders explain that after the reviews were published, they extended a job offer to a candidate for a management position, but the candidate declined the offer and cited the reviews as a reason for doing so."
A statement from Glassdoor via a New York public relations firm said the company was dismayed by the Court's decision and fights to protect the identities of users.
"We are deeply disappointed in the Court's decision, which was effectively decided under New Zealand law," the statement said.
"We note that, contrary to Zuru's contentions, the unflattering workplace experience reviews describing working at Zuru were authored by multiple former Zuru employees."
The statement said the company had won the majority of similar cases brought against it.
"We typically prevail in the vast majority of these types of cases. To date, we have succeeded in protecting the anonymity of our users in more than 100 cases filed against our users."
The company aimed to " empower job seekers in New Zealand and around the world to have access to information from those who know companies best," Glassdoor said.
Zuru was started by the Mowbrays in a Waikato Shed nearly two decades ago.
It is now among the world's biggest toy makers and is headquartered in Shenzhen, China.
Siblings Anna, Matt and Nick Mowbray remain directors, Companies Office records show.
