Pridi Phanomyong was born in Ayutthaya Province, the second of five children.
He had two half-siblings from his father's minor wife.
In 1915, following a royal decree issued by King Vajiravudh, Pridi and his family dropped "Nai" from their names.

After having graduated with an LLB from Thai Royal College of Law, he received a government scholarship to study law and political economy at Sciences Po in Paris.
He earned a PhD in 1927 and returned to Siam that year to work for the Ministry of Justice.
He quickly rose in rank, and was granted the royal title Luang Praditmanutham (Thai: หลวงประดิษฐ์มนูธรรม).
He also began assembling a group of fifty civil servants who wanted to replace the absolute monarchy with a constitutional monarchy.
Pridi Phanomyong was born in Ayutthaya Province, the second of five children. He had two half-siblings from his father's minor wife. In 1915, following a royal decree issued by King Vajiravudh, Pridi and his family dropped "Nai" from their names.
After having graduated with an LLB from Thai Royal College of Law, he received a government scholarship to study law and political economy at Sciences Po in Paris. He earned a PhD in 1927 and returned to Siam that year to work for the Ministry of Justice. He quickly rose in rank, and was granted the royal title Luang Praditmanutham (Thai: หลวงประดิษฐ์มนูธรรม). He also began assembling a group of fifty civil servants who wanted to replace the absolute monarchy with a constitutional monarchy.
Pridi Banomyong