CAIRO—Egypt’s foreign ministry on Sunday harshly rejected international criticism of a court’s decision to sentence a team of Al Jazeera journalists to three years in prison, summoning the British ambassador to Egypt for condemning the verdict.

Mohamed Fahmy, the former Cairo bureau chief for the Qatar-based network, Baher Mohamed, who worked as a cameraman, and Peter Greste, an Australian correspondent deported earlier this year and convicted in absentia, were widely expected to be cleared of all charges on Saturday in Cairo.

The British ambassador, John Casson, was one of a chorus of international officials and human rights groups who were sharply critical of the verdict.

His statements on the court’s decision were “unacceptable interference” in Egypt’s judiciary, the foreign ministry said in a statement on Sunday, “inconsistent with diplomatic norms and practices.”

It is typical for Egypt’s foreign ministry to condemn criticism of the country, but it hasn't summoned a foreign ambassador since President Abdel Fattah Al Sisi took office in 2014.

Egypt “rejects any foreign criticism of judicial verdicts,” the foreign ministry said in comments posted to its official Twitter account.

The comments came as lawyers for Mr. Fahmy, a dual Egyptian-Canadian national who gave up his Egyptian citizenship in hopes of expediting a deportation, said they have submitted paperwork petitioning for a deportation.

The three journalists were found guilty on charges that included broadcasting false news and operating without licenses. They have all denied the charges.

In delivering Saturday’s verdict, Judge Hassan Farid said the defendants “were not journalists at all” and had operated illegally and broadcast false news intended to harm Egypt’s image abroad.

Al Jazeera condemned the decision. “Today’s verdict defies logic and common sense,” Al Jazeera Media Network’s Acting Director General Dr. Mostefa Souag said. Network officials said they would appeal the verdict in the Court of Cassation, Egypt’s highest court.

Mr. Fahmy and Mr. Mohamed were present in the Cairo courtroom. They had been free on bail during the trial, but were quickly taken into custody after the verdict, as their families gasped and shouted disapproval of the decision.

Fellow defendants Sohaib Saad, Khaled Mohamed and Shadi Abdel Hamid, Egyptian students accused of providing the network with footage of protests shot on cellphones, were also sentenced to three years each. Two other students were acquitted.

The decision closes a case that has been seen as politically motivated and which has brought international condemnation on Mr. Sisi’s government, even as he sought to project an image of democratic reform in the wake of the 2013 military coup that brought him to power.

Families and supporters of the journalists derided Saturday’s decision. “There was no due process at all,” said Mr. Fahmy’s brother, Adel Fahmy. “This was a joke of a trial.”

Marwa Omara, Mohamed Fahmy’s wife, tearfully appealed to Egypt’s president to pardon her husband or deport them both to Canada. “All I’m asking for is justice,” she said. “He did nothing wrong and even gave up his Egyptian citizenship. We want what Peter [Greste] was given.”

Canada on Saturday called for the immediate release of Mr. Fahmy. “Canada is disappointed with Mohamed Fahmy’s conviction today. ‎This decision severely undermines confidence in the rule of law in Egypt,” said Lynne Yelich, Minister of State for Foreign and Consular Affairs after the verdict. “The government of Canada continues to call on the Egyptian government to use all tools at its disposal to resolve Mr. Fahmy’s case and allow his immediate return to Canada.”

Meanwhile, the European Union said the verdict was a “setback for freedom of expression in Egypt.”

The Al Jazeera trial has drawn international condemnation from human and journalists’ rights groups and focused attention on Egypt’s judiciary, which has been accused by the defendants and legal analysts of acting to suppress popular dissent on behalf of the Sisi administration.

Mr. Sisi has repeatedly said the judiciary is an independent institution that is beyond his control.

Last year, he obtained legal authority through decree to deport foreigners accused of crimes in Egypt. It was first applied in Mr. Greste’s case and was seen as a concession to international critics of the trial.

Separately, Egypt announced on Sunday that it will hold parliamentary elections in two rounds in October and November. It will be the first parliament in Egypt in more than two years.

—Dahlia Kholaif contributed to this article.

Write to Tamer El-Ghobashy at tamer.el-ghobashy@wsj.com