Authorities in the Gulf state say more women are falling into this category: some 60 percent, according to the latest statistics, raising concerns among officials and sparking online debates as to why.
The issue has been the focus of discussions for weeks at the Federal National Council, the country's appointed consultative body, where members are scrambling to find a solution to what they believe could be a serious demographic problem.
"This is very worrying," FNC member Said al-Kitbi told AFP, adding that there are now more than 175,000 Emirati women who are over 30 and unmarried.
Though he conceded that being a "spinster" is "not a bad thing in itself", he argues that the demographic consequences of these women not having children is the real problem.
The United Arab Emirates is home to more than eight million people, only 950,000 of them UAE citizens. The rest are foreign, and young Emirati men are increasingly choosing to marry them instead.
The latest government statistics show that at least 20 percent of UAE men are marrying non-Emiratis.
The reasons behind this growing trend of spinsterhood are not entirely clear.
UAE planning ministry statistics show that in 1995, only 20 percent of women over 30 were unmarried. By 2008, that figure was 50 percent.
Some evidence suggests that excessively high dowries are preventing men without the means from choosing a spouse.
The latest survey by the UAE Marriage Fund, a government institution that provides financial assistance to those who want to marry but cannot afford to, showed that 87 percent of respondents blamed high dowries for low marriage rates among Emirati women.
The government has imposed a $14,000 ceiling on dowries, but many families still demand much more -- in some cases over $135,000.
"One of my friends is still paying his dowry bill and he's been married nine years," said Ali Mansouri, 30.
-- 'Lost between tradition, modernity' --
To address the rising costs of marriage, the government has ordered that each Emirati man who wants to marry be given $19,000 -- but on condition that it is his first marriage.
However, the Marriage Fund will make an exception for men who married women who cannot conceive. In this case, the fund will give the man money to take a second wife.
In the UAE, as in many Muslim countries, polygamy is sanctioned by both religion and the law.
The Marriage Fund also routinely organises mass marriages to help cut costs and reduce the burden on individual men seeking a wife.
There are also other reasons why Emirati women are not getting hitched before 30: they are opting for education and a career before settling down.
Take Mansouri: he is looking for a wife but says he prefers that she not work. And if she insists, he would rather that she do so part-time only.
"Most men who succeed in their lives have wives who do not work, or do so from home," Mansouri said. "It's impossible to reconcile work and family life."
A survey of 200 medical students at the UAE University showed that 57 percent of respondents believed a desire to pursue higher education and a career were the main reasons why UAE women are not marrying before 30.
The students, however, said they would not classify a woman as an "old maid" until she is 32.
"We're a little lost between tradition and modernity," said Wafa Khalfan, a single Emirati in her twenties.
"Many girls are pretty and all grown up but they can't find a spouse," she said, adding that "if liberal they're considered easy, and if they're conservative, men think they're too uptight."
FNC member Kitbi says that the problem could be "the girls themselves, as they prefer to complete their university studies and work rather than get married."
He said it also seems that young Emirati men "prefer a woman who does not work."
Tribal traditions, meanwhile, have made an already difficult situation worse.
Some families refuse to marry off "their younger daughter before the first-born," while still others will not allow their children to marry into a family of "lower social status", Kitbi said.
Some of the most interesting statistics from a separate survey of 200 medical students show that many men and women believe polygamy may be the solution.
Some 73 percent of those surveyed said encouraging polygamy was a reasonable solution to the spinster crisis -- and 59 percent of women surveyed agreed.
For Emirati writer and journalist Al-Saad al-Minhali, however, polygamy is not the answer.
"This is not a solution," she said. "Marriage is a personal choice and should not be used to satisfy a national agenda."