In the second-biggest Muslim country, Pakistan, newspapers are publishing Valentine's Day messages and hotels have made special arrangements for customers on Saturday.
Internet clubs said they expected a rush of young clients on the day to exchange greetings with loved ones, and mobile phone providers are looking forward to a similar surge in business.
But officials from Pakistan most influential political grouping, the six-party religious alliance Muttahida Majlis-i-Amal (MMA), disapprove of the celebrations.
"Any contact between opposite sexes outside marriage is forbidden in Islam, so Valentine's Day is not for us," the parliamentary leader of the MMA, Maulana Fazal al-Rahman, told AFP.
"It's all right if a husband or a wife express their love to each other, but unmarried boys and girls aren't supposed to do it."
"Any contact between opposite sexes outside marriage is forbidden in Islam, so Valentine's Day is not for us"
Maulana Fazal al-Rahman, parliamentary leader of MMA
The MMA, which rules the deeply conservative North West Frontier Province bordering Afghanistan, banned New Year celebrations this year and the previous year in the province.
But despite the official condemnation, shops in the provincial capital Peshawar were openly selling ornamental Valentine's gifts, red heart props and chocolates, residents said.
And florists, bakeries, eateries and gift shops in big cities like Karachi, Lahore and Islamabad are waiting for a rush of customers on Valentine's Day.
In such societies, the quest to find that perfect Valentine hideaway can be difficult.
Not so long ago, Valentine's Day was virtually unheard of in Bangladesh, the world's third largest Muslim-majority country. But in recent years, it has been enthusiastically embraced by teens and twenty-somethings.
A Kuwaiti couple seem unmoved
by a shopping mall's decorations
Bangladesh's younger generation is highly receptive to Western culture, with interest partly fuelled by widespread access to satellite television channels.
Dhaka's many new cafes and restaurants have been a gift for young dating couples desperate to shake off the attention of their ever-watchful parents.
"We only opened a few months ago but I'm sure we will be completely full on Valentine's day with couples having ice cream and cappuccinos," said Reza Karim, manager of a new Italian-themed cafe in Dhaka.
"They will come here for a fun, romantic time. In places like this they can be alone together without their families watching all the time, although of course they will probably tell their parents they are going to be with their friends."
At Dhaka's Asparagus restaurant, manager Kazi Nazrul says Valentine's Day is getting busier each year. "It's getting more and more popular all the time. Young people like to mark it because they see it as a bit of fun," he said.
"Rich families don't really mind their children meeting their girlfriend or boyfriend. But middle class and working class parents disapprove, so couples meet secretly most of the time, not just on Valentine's Day."
Little is known of Valentinus, the third-century priest who is believed to have been canonised the patron saint of love. Legends, however, abound.
One says he was beheaded for defying Roman Emperor Claudius II's prohibition on soldiers getting wed after secretly marrying a few troops to their sweethearts.
Another legend says he miraculously restored the sight of his jailer's blind daughter and fell in love with her. On the eve of his execution, on 14 February, he wrote her letter expressing his undying love and signed it 'Your Valentine', a custom that continues even today.
Resistance to celebrating Valentine's Day is not restricted to conservative Muslims. Hindu nationalists in India claim the Western holiday promotes promiscuity, and in recent years they have marked the day by trashing shops, burning cards and chasing hand-holding couples out of restaurants.