Leyla is the Turkish, Persian, and Azerbaijani spelling of Layla — from the Arabic laylah, meaning "night." The famous 7th-century Arabic love story Layla and Majnun tells of a beauty whose hair was black as night.
Leyla is enormously popular in Turkey, Iran, and across the Muslim world. In the U.S. the Y-spelling has been rising rapidly — today Leyla sits in the U.S. top 400.
Leyla does not currently appear in the US Social Security Administration's top 1,000 girls' names, so we don't publish a US rank or birth count for it. That says nothing about the name's standing elsewhere in the world — only that it sits outside the ranked US data we rely on.
In Pythagorean numerology the letters of Leyla reduce to 1, The Leader. This is a traditional interpretive system, not a factual claim about the name.