Central Scotland list MSP Monica Lennon joined striking college support staff as members of trade unions Unison and the GMB demonstrated outside the Scottish Parliament.
Around 2,500 support staff took part in industrial action on Tuesday, with further action planned for the end of October.
The dispute follows colleges awarding lecturing staff a £450 flat rate rise in May, while most support staff have been offered a flat rate of £230.
Staff from New College Lanarkshire were among those who took part in the action.
Ms Lennon said: “These classroom assistants, technicians and workers are the backbone of their colleges and deserve fair pay and parity with their teaching colleagues.”