98.9% of the population in Tegal Regency is Muslim.

The Muslim population in Tegal Regency, as of December 31, 2023, was recorded at 1.71 million. Compared to the previous year, the number of Muslims in the regency/city increased by 37,353.

According to data from the Directorate General of Population and Civil Registration (Ditjen Dukcapil) of the Ministry of Home Affairs, the proportion of Muslims in this regency/city reached 98.9 percent of the total population in 2024, which numbered 1.73 million.

In terms of distribution across the districts of Central Java, the proportion of Muslims in Tegal Regency ranks fourth.

The following is a list of the population of Central Java by religion in 2023:
* Islam 1,708,725 (98.91%)
* Protestant 4,444 (0.26%)
* Catholic 2,464 (0.14%)
* Buddhist 453 (0.03%)
* Hindu 284 (0.02%)
* Confucian 213 (0.01%)
* Other Beliefs 54 (0.0%)

Compared to other regions in Central Java, the Muslim population in this regency/city is among the top four.

Other regions with the top 10 largest Muslim populations in Central Java Province are: Brebes Regency (2,049,083), Cilacap Regency (2,006,687), Banyumas Regency (1,828,568), Pemalang Regency (1,571,040), Grobogan Regency (1,499,245), Semarang City (1,485,169), Kebumen Regency (1,420,918), Pati Regency (1,341,492), Magelang Regency (1,298,638), and Demak Regency (1,236,963).