Petrus Josephus Mattheus "Piet" Aalberse Sr. (27 March 1871 – 5 July 1948) was a Dutch politician of the defunct General League of Roman Catholic Caucuses (ABRK) later the Roman Catholic State Party (RKSP) and later co-founder of the Catholic People's Party (KVP) now merged into the Christian Democratic Appeal (CDA) party and jurist.
Petrus Josephus Mattheus "Piet" Aalberse Sr. (27 March 1871 – 5 July 1948) was a Dutch politician of the dissolved General League of Roman Catholic Caucuses (ABRK), later the Roman Catholic State Party (RKSP), and co-founder of the Catholic People's Party (KVP), which is now part of the Christian Democratic Appeal (CDA) party, and jurist.