John of Kastav (; ; ) was a 15th-century Istrian artist, a native of Kastav (Croatia).
He painted the frescoes in the Church of the Holy Trinity, Hrastovlje, which included a famous Danse Macabre. According to the inscription, which identifies the artist as magister Johannes de Castua, the frescoes were commissioned by TomiÃÂ VrhoviÃÂ, the parish priest of Kubed, and completed in 1490.