A federal judge in Maryland granted a preliminary injunction on Monday barring top officials at the Education Department and the Office of Personnel Management from turning over sensitive data to Elon Musk and members of his Department of Government Efficiency team while a privacy lawsuit continues.

The order was the latest development in a category of lawsuits that have taken aim at Mr. Musk’s access to federal databases containing personal information about U.S. citizens. The suits have largely succeeded thus far in securing rulings blocking Mr. Musk’s team from that type of data.

In an opinion accompanying the order on Monday, Judge Deborah L. Boardman of the Federal District Court for the District of Maryland wrote that the Privacy Act of 1974 clearly required stronger protection of personal and financial data that could be vacuumed up in Mr. Musk’s efforts to scour agency records.

The American Federation of Teachers had sued to halt those efforts, saying that its members routinely submitted sensitive data to the department for help with student loan forgiveness and other programs, and had not consented to their data being scrutinized by Mr. Musk’s team, which despite its name is not an executive-branch department. Judge Boardman issued a restraining order last month and extended it on Monday, citing Congress’s reasoning when it passed the Privacy Act more than 50 years ago.

“Those concerns are just as salient today,” she wrote. “No matter how important or urgent the President’s DOGE agenda may be, federal agencies must execute it in accordance with the law. That likely did not happen in this case.”

Federal judges in a number of cases have been sympathetic to arguments that Mr. Musk’s sweep through federal data systems have come at the expense of ordinary people who handed their financial records and personal details over to the government for routine services.

Last week, a judge ordered the Social Security Administration to ensure that any data given to Mr. Musk’s team was anonymized or redacted first. And last month, a judge in a another case took similar steps to protect taxpayer information stored at the Treasury Department.

Lawyers behind those various challenges have argued that the injunctions are increasingly urgent, especially in light of fears that data submitted by private citizens could be used for other purposes beyond a routine audit, including identifying and targeting undocumented immigrants for deportation. Over the weekend, a draft report of a deal between the Internal Revenue Service and the Immigration and Customs Enforcement office indicated that the Trump administration was already moving to use data for that purpose, even without Mr. Musk’s team serving as a go-between.

Randi Weingarten, the president of the American Federation of Teachers, said in a statement on Monday that Mr. Musk and his team “have been running roughshod over Americans’ privacy.” The judge, she said, had acted to maintain a firewall between those efforts and the data of tens of millions of people held by the Education Department.

In her ruling, Judge Boardman reiterated that the union appeared likely to prevail in the case. But as in other cases, the rapid pace at which the Trump administration has moved to dismantle agencies and outrun the courts could limit some of the practical effects of the order.

Already this month, top officials at the Education Department rushed to cut the agency’s work force in half. And an executive order President Trump signed last week directed the agency’s leaders to find ways to spin off some of its functions, potentially moving some of the databases at issue in the lawsuit to other departments, such as the Small Business Administration or the Department of Health and Human Services.