Workers from Unite, Unison and the GMB are holding a mass rally at East Dunbartonshire Council headquarters today (Thursday).
The action in Kirkintilloch coincides with a meeting of the full council on the first day of four 24-hour strikes.
All schools and nurseries in East Dunbartonshire are closed, as are leisure centres, libraries, museums and community hubs.
The dispute is over planned changes to workers’ terms and conditions.
A statement from East Dunbartonshire Council said: “In an effort to avoid strike action, the council made a further offer to the trades unions to allow further time for negotiation on the areas being identified as of most concern.
“To enable those further negotiations the strike would need to be suspended.”
Simon Macfarlane, UNISON’s regional organiser, said: “There has been an overwhelming response today from UNISON members.
“We had hoped that the council would see sense and we continued talking in good faith.
“We were making progress, but, at the latest talks, workers’ terms and conditions did not improve, so the strike action went ahead.”
The strike is due to continue tomorrow, Monday and Tuesday.