Their parents are taking their betrothal seriously, and even arranged an engagement ceremony and bought rings which the couple exchanged.
Five-year-old Khalid met Hala, three, while he was holidaying with his parents in Lattakia, on the Mediterranean coast of Syria.
He is said to have fallen for Hala and told his parents that he wanted to marry her.
Speaking to Gulf News, Khalid's father Juma said: We know Khalid or Hala might change their mind in the future, but what we do know at this stage is that they are very happy to talk to each other every day.Khalid is waiting until he is 15 to marry Hala.
He was said to be so lovesick on his return home that he refused to go back to his nursery unless Hala joined him.
Instead of treating it as a case of premature puppy love or kindergarten role-playing, his parents called Hala's mother to seek her opinion.
'She said her daughter had developed similar symptoms of loneliness and the family would be very happy to see them engaged,' said Juma.
The families returned to Lattakia for the engagement ceremony. Juma said that all the arrangements went smoothly, and that the children exchanged rings like adults.
He said: 'My wife and I got Khalid after 20 years of marriage, in a complicated pregnancy. I vowed to have my child engaged at the age of five if he was a boy and to marry him to a woman of his choice.'
The UN recommends that countries adopt a minimum age for marriage of 18 for both sexes.