DJERBA, Tunisia—By the hundreds, they gathered for a pre-wedding party on a resort island in Tunisia. Here, in the heart of the Muslim world, the crowds were speaking Arabic. The band was Arab too, playing boisterous Arabic melodies.

But the revelers were Orthodox Jews—as devout as they come.

Per custom, the bride-to-be, Oshrit Uzan, had quit her job running her own beauty salon to prepare for her new life. She might return to work, she mused, but her husband must approve: “I will need permission,” she said.

Isolated on a small niche of North Africa’s largest island, the Jews of Djerba have been called the last Arab Jews—and it is hardly an exaggeration. Across the rest of the Middle East, Jewish communities have been vanishing over the past half century, since the creation of Israel. Before then, there were more than 850,000 Jews living in the Arab world. Today, there are between 4,000 to 4,500, according to Justice for Jews from Arab Countries, a nonprofit advocacy group.

Some countries, such as Algeria and Libya, which once had sizable Jewish populations, have virtually no Jews within their borders. Egypt, which through the late 1940s had 75,000 Jews active in the country’s economic and social life, is down to a few dozen. Only Morocco, once home to 265,000 Jews, has a community of 2,500 left. Many are elderly or middle-aged.

As other Tunisian Jews moved away to Israel and France for fear of persecution, the Jews of Djerba stubbornly clung to the promise of their own future. A community that had dwindled to fewer than 700 Jews by the mid-1990s—from a high of about 5,000 in 1948—began to grow slowly but surely. While there were and still are departures, they are outweighed by the young families choosing to stay. Today, the island’s Jews number roughly 1,000, local leaders estimate.

Arab countries have seen their Jewish populations dramatically decrease since 1948 SOURCES: STANLEY URMAN JUSTICE FOR JEWS FROM ARAB COUNTRIES; SERGIO DELLAPERGOLA, HEBREW UNIVERSITY

Mounting concerns about anti-Semitism in France—which culminated recently in the massacre of several Jews in a Parisian kosher market—underscore what the Chief Rabbi of Tunisia has been saying for years: That no place is safer or more hospitable for Jews.

“The Jews of Djerba are concentrated in one area, so the government is able to protect us,” says Haim Bittan, the Chief Rabbi. A resident of Djerba, Rabbi Bittan also believes that the community’s deep spirituality offers it protection. “We have faith in God, that if we keep his laws and commandments, he will guard us from evil,” he says.

The central government in Tunis has long seen value in having a stable Jewish population. Even after the 2011 revolution ousted longtime President Zine El Abidine Ben Ali —the first casualty of the Arab Spring—the new leaders sought to assure Tunisian Jews that they were safe.

Watch a video about the thriving Jewish community on the island of Djerba. Photo: Daniella Zalcman for The Wall Street Journal

Djerba has enjoyed a lucrative tourist industry and Tunisia has been keen to preserve it by stressing its tolerance and moderation. Having a sizable Jewish community is key in that goal.

Djerban Jewish leaders are concerned about assimilation, so contacts with the 150,000 Muslims on the island are limited. Clustered in the Hara Kebira, the main Jewish quarter, they speak Arabic as well as Hebrew; a few speak French.

Relations between Jews and Muslims are complex—proper and respectful, though not especially close. Jewish men work alongside Arab merchants in the souk, for example, and enjoy amiable ties with Muslim customers.

With its low-lying houses and narrow, unpaved streets, the Hara Kebira is modest. While not walled in, it is insular and self-contained. Little boys run around in skullcaps; women wear long skirts, and scarves, in the manner of Orthodox Jews. And there are over a dozen working synagogues. Many men make a living both making and selling jewelry.

In Djerba, Modern Brides Adhere to Ancient Customs In the Orthodox Jewish community in Djerba, Tunisia, a party for bride-to-be Oshrit Uzan took place last summer. The friends and relatives—women only—plied her with jewelry such as gold rings and precious bracelets, and in return received a blessing from her. Daniella Zalcman for The Wall Street Journal 1 of 9 • • • • • 1 of 9 Show Caption In the Orthodox Jewish community in Djerba, Tunisia, a party for bride-to-be Oshrit Uzan took place last summer. The friends and relatives—women only—plied her with jewelry such as gold rings and precious bracelets, and in return received a blessing from her. Daniella Zalcman for The Wall Street Journal

In 2002, an al Qaeda affiliate sent a truck bomb loaded with explosives to attack the legendary Ghriba synagogue, located in the Hara Sgira, the smaller of Djerba’s two Jewish quarters. Nearly two dozen people were killed, most of them German tourists, and many more were wounded. The government beefed up security in response. Only last spring, two Jewish merchants were stabbed by Muslim assailants. Although local authorities said the attacks weren’t motivated by religion, the violence still made the community anxious.

Over the longer term, the greatest threat to Djerba’s Jews may come, not from without, but from within. Jews have lived on this storied island for centuries and, some believe, since Biblical times. Ancient traditions guide every aspect of Djerban Jewish life, but modernity is slowly encroaching. Laptops, iPhones and TV sets are ubiquitous.

Perhaps the biggest question mark revolves around the role of women in society. Largely absent from the workforce, Djerba’s Jewish women generally are expected to lead traditional lives tending to husbands and families.

The result has been an off-the-charts birth rate. Women here bear an average of four to five children, according to local leaders. Some have 10 or 12. That has contributed to a virtual population explosion in recent decades, with roughly 50% of the population 20 years of age or younger, according to local leaders.

In Tunis, by contrast, only 300-400 Jews remain—down from tens of thousands. Many of them are elderly and frail.

Youssef Wazan, the president of the community, argues that Djerban Jews have done better than other Arab Jews precisely because they have fought against the lure of modern times—including assimilation and the changing role of women.

“Listen, the Jews in Tunisia, they had their freedoms…and they all left,” he says. “Our synagogues are full every day and on the Sabbath, we don’t work—nothing. If you look at France you don’t see that even on Yom Kippur. That is why we don’t want modernity.”

And yet, at the fringes of society and in subtle ways, Djerban women are evolving. Two agents of change are cousins Alite and Hanna Sabban, who have fought to bring greater educational opportunities to the girls of Djerba.

This archival photo captures two young girls in Djerba’s Jewish community in the 1950s, holding a baby. Photo: American Jewish Joint Distribution Committee

They are far from radical. Married to two brothers, Hanna, 34 years old, has four children, while Alite, 33, has seven. Neither has an advanced education. Both are deeply observant, and embrace the importance of religion and the traditional role of Djerban Jewish women as wives and mothers. But they are also critical of their culture’s failings with respect to women and feel that even within the confines of Djerba’s conservative beliefs, there is much room to evolve.

Educating girls hasn’t been a high priority in Djerba’s Jewish community. Historically, in fact, they weren’t educated at all, and most were illiterate until well into the 20th century.

For boys, an education, at least a religious one, has always been a key part of life on Djerba. They study Hebrew and the Torah from morning to night, in classes taught by rabbis. That education was formalized with the establishment in the 1960s of modern-day religious schools known as “Yeshivot.”

But women’s education didn’t exist. In the early 1950s, resident David Kidouchim started a part-time school for girls teaching them to read and write in Hebrew. Though it was only two hours a day, his school was seen as transformational, and he became a local hero.

To the Sabban women, it is no longer enough. “When a girl goes to school for two hours, what can she do?” Alite asks. “We wanted more studies, we wanted for the girls to develop academically.”

They speak from personal experience. Growing up, Hanna was the luckier one. Her parents allowed her to attend the Arab public lycée outside of the main Jewish quarter, so she received more of a secular, full-time education. But she left at 14, she says, before she could get the prized baccalaureate. The two women bonded because of shared frustrations and a sense that life for a Jewish girl could be better—even within the confines of faith and tradition.

Hanna Sabban and her sister-in-law Alite Sabban stand in the middle of an abandoned house they recently purchased in hopes of establishing Djerba’s first full-time school for girls. Photo: Daniella Zalcman for The Wall Street Journal

As a girl of eight, Alite did enjoy a taste of a different type of education, when her family left Djerba to live in Marseille. For two years in France, Alite was like every French child—attending school from morning to late afternoon or early evening. “I loved school—I loved the life of a schoolgirl,” she says. Then her parents decided to return to Djerba, and she was back in the “Hara” with nothing to do day after day after her classes.

Hanna fondly remembers how she and Alite would sit by an abandoned house and chat about the school they were going to build there one day. Then finally, in 2006, at the time both in their mid-20s, they decided to take the plunge. They began with organizing weekly classes for a few dozen girls, then started a more formal effort with 15 students. But several dropped out and they were left with nine or 10.

The women faced numerous obstacles. Fundraising proved difficult and was halted well short of its goal—a result of red tape that bogged down their plan to buy the house from its French owner.

They also struggled to find competent teachers from within their community.

Some of the most qualified candidates were married with children. Hanna and Alite went ahead and hired them anyway, despite the lingering taboo of women working outside the home.

But the biggest hurdle has been money. Neither of the women had the financial means to open a school. So Hanna and Alite started small, offering classes in a synagogue.

In Djerba, Jewish Life Clings to Tradition In Djerba’s Hara Kebira, the main Jewish quarter, both Jews and Muslims live side by side. Daniella Zalcman for The Wall Street Journal 1 of 9 • • • • • 1 of 9 Show Caption In Djerba’s Hara Kebira, the main Jewish quarter, both Jews and Muslims live side by side. Daniella Zalcman for The Wall Street Journal

Along the way, the Sabbans picked up a crucial ally. The American Jewish Joint Distribution Committee, or “the Joint” as it is commonly known, is an international relief organization that has played a quiet but important role in supporting Djerban Jews for several decades. The enormous New York-based outfit says it spends hundreds of millions of dollars each year on needy or endangered Jewish communities.

Yechiel Bar-Chaim, a 69-year-old American who was the Joint’s man in Tunisia for many years, says that at some point—he doesn’t remember the year—Hanna Sabban approached him about starting a new girl’s school. After a couple of discussions, and witnessing some of the classes the women were already running, he was on board.

“There was a new generation ready for a new level of learning and personal development,” Mr. Bar-Chaim recalls.

Rabbi Haim Bittan, the Chief Rabbi of Tunisia who is based in Djerba, runs a school for boys, pictured above. He maintains there is nowhere safer in the world for Djerba’s Jews than their island community. Photo: Daniella Zalcman for The Wall Street Journal

Life in the Jewish quarter depends on whether the Chief Rabbi approves or disapproves of a venture. Rabbi Bittan says backing a new girl’s school was easy. His rationale: A school within the Hara would eliminate the need to send girls to public school.

Over time, Mr. Bar-Chaim arranged for the Sabbans’ makeshift school to obtain textbooks. Then came supplies like Xerox machines, computers, even air conditioners. The women weren’t shy about making demands of the Joint, he says, recalling numerous requests from them for books and other basics.

The Sabban women’s school is housed in three separate locations—including a basement and a large converted garage of a private home. Teachers run through the streets every couple of hours to their different classes. In the garage, some classrooms are windowless and air conditioning is spotty. The computer “lab”—with new Lenovos sent by the Joint—is a small enclave in a hallway.

In recent years, the Joint has spent about $100,000 to $200,000 annually on various projects, and in 2013, it allocated $338,748. Most of the latter sum says Mr. Bar-Chaim, was raised specially for the Sabban women’s school project.

Mr. Bar-Chaim also became an ally in their efforts to overcome Djerba’s resistance to change. Anxious not to step on toes, the women said they worked out a complex plan in which the girls could attend both the new school and the existing, two-hour-a-day school. The girls would go in the mornings to Mr. Kidouchim’s school for the requisite couple of hours then head over to classes at the new school.

Enrollment grew, and in September 2012 Hara residents gathered for a joyful naming ceremony—the Sabbans called their school “Kanfei Yonah”—which means “On the Wings of a Dove” in Hebrew.

The school has its critics. Simon Saghroun, the Jewish Quarter’s physician, points out that it isn’t accredited by Tunisian authorities. Girls who go there can’t get a diploma that would enable them to continue their studies elsewhere. He questions the founders’ claims that their school rivals and even surpasses what public schools offer.

Simon Saghroun is the sole Jewish doctor in the main Jewish quarter. He believes Djerba’s community is unique in the Arab countries because it is thriving and growing even as most others have vanished. Photo: Daniella Zalcman for The Wall Street Journal

“You need an organization, and controls—you need to have accredited teachers with diplomas,” Dr. Saghroun says. Concerned about assimilation, they don’t hire outsiders and rely on inexperienced, untrained young Djerba Jewish women, he says. Even so, considering the alternative—girls staying at home—“it is better than nothing,” he acknowledges.

Mr. Bar-Chaim, who recently retired from the Joint, dismisses the criticism, saying that the school offers “rigorous” studies.

The Sabban women say they hope to obtain some sort of accreditation, perhaps from Israel, so girls can eventually pursue more advanced studies if they wish.

“The advance of education for girls has to bring certain changes—and no one is quite sure what,” says Mr. Bar-Chaim. Timing is critical. Already, he notes, some young women have left the community, tired of chafing against traditional limits. One young resident, Emanuella Haddad, frustrated at not being able to leave Djerba to pursue higher studies, has enrolled in law school—online. She is an example of a young woman who has chosen to defer marriage. “I’d like to have a family, but it’s not my first goal,” she says.

On a positive note, more than half the school staff is married—a stark departure from the old days. Pregnant teachers are encouraged to return to work almost immediately after giving birth.

Late last year, the Sabban women finally obtained the sales papers they needed for the new full-time school—and the dilapidated house of their dreams is theirs. Once they get a local building permit, they hope to demolish the existing structure and build. They are still short of the €500,000, or nearly $600,000, they have budgeted, so their plan is to construct one floor at a time, and one wing at a time.

Alite remains anxious. She recalls as a little girl watching from her house the children whose parents sent them off to public school early in the morning. She felt jealous and wondered why she couldn’t be one of them. “I thought why not me, why not other girls?” she recalls.

Still, there is the question of what Djerba’s young women can ultimately achieve. “I don’t want all our girls to be lawyers,” says a teacher, Geoula Trabelsi, who has been with the school since its inception. “I want them to be happy, to be women of faith.”

A young girl wearing a traditional shawl in Djerba, circa 1951. Photo: Stanley Abramovitch/American Jewish Joint Distribution Committee

Corrections & Amplifications

An earlier version of this article incorrectly said that Hanna Sabban had seven children and that Alite Sabban had four. (Feb. 13, 2015)

Write to Lucette Lagnado at lucette.lagnado@wsj.com