Justin of Siponto was an early fourth-century Christian bishop and presbyter who resided in Siponto. Along with his siblings, Florentius and Felix, he was part of a family dedicated to the faith, which also included his niece, Justa. While historical accounts of his life are often viewed as legendary, he is recognized as a saint within the Catholic tradition. After living in Siponto, he eventually moved to Chieti, where his religious leadership was established.