Miss Grand Phra Nakhon Si Ayutthaya (Thai: มิสแกรนด์พระนครศรีอยุธยา) is a Thai provincial beauty pageant which selects a representative from Phra Nakhon Si Ayutthaya province to the Miss Grand Thailand national competition.

[4] Phra Nakhon Si Ayutthaya representatives have yet to win the Miss Grand Thailand title.

[5] In 2016, after Miss Grand Thailand began franchising the provincial competitions to individual organizers, who would name seventy-seven provincial titleholders to compete in the national pageant, the license for Phra Nakhon Si Ayutthaya province was granted to an entrepreneur Thippawee Suphanakorn, who organized the first Miss Grand Phra Nakhon Si Ayutthaya contest on April 24, 2016, at the Ayutthaya City Park,[4] and named Thanisa Panyaphu the winner.

[7] The following table details Miss Grand Phra Nakhon Si Ayutthaya's annual editions since 2016.

The following is a list of Phra Nakhon Si Ayutthaya representatives who competed at the Miss Grand Thailand pageant.