Demographics
According to the Palestinian Central Bureau of Statistics, Sinjel had a population of approximately 5,743 inhabitants in 2007. As a result of high birth rates, the town has grown substantially in population.
Population growth in Sinjel (1922-2007)
| Year | Population |
| 1922 | 934 |
| 1934 | 1,071 |
| 1945 | 1,320 |
| 1961 | 1,778 |
| 1967 | 1,823 |
| 1987 | 3,773 |
| 1997 | 4,933 |
| 2005 | 5,371 |
| 2007 | 5,743 |
Sinjel is composed of nine clans (Hamolah): Awashra, Asfour, Elwan, Fuqaha, Karakra, Khalil, Masalmeh, Shabana, Tawafsheh.
The town’s population is entirely Muslim.