Crowds estimated to number in the tens of thousands led by local administrators gathered in several in provinces on Wednesday in a show of loyalty to the royal institution.
The royalist demonstrations, staged in response to recent calls by some student protesters for reform of the monarchy, took place in provinces including Chiang Mai, Chon Buri, Lampang, Nan, Narathiwat and Songkhla.
Some of the rallies were organised as part of ceremonies to mark the 120th birthday anniversary of late Princess Srinagarindra, the grandmother of His Majesty the King.
In Songkhla, thousands of people wearing yellow, the Thai traditional birthday colour of the King, showed up in Ranod and Sathing Phra districts. In Narathiwat, an estimated 20,000 yellow-clad people marched in Sungai Kolok district.
Similar gatherings were planned in provinces before the end of this month.
The royalist demonstrations come after recent mass rallies in Bangkok and other parts of Thailand calling for Prime Minister Gen Prayut Chan-o-cha to quit. Some of the protest leaders have also called for reform of the royal institution.
