What is the strike about?
The workers are striking over a long-running equal pay dispute.
The council adopted the Workforce Pay and Benefit Review (WPBR), implementing its job evaluation-based pay and grading system in 2006 with the aim of ensuring men and women received equal pay for jobs of the same value.
However, some women claim they were paid £3 an hour less than men in similarly graded roles.
What action was taken before the strike?
In May 2017, the Court of Session ruled the WPBR discriminated against female workers.
The council decided it would not appeal the decision of the court and would, instead, commit to settling the outstanding equal pay claims and introduce a new system.
In the same month, the SNP became the biggest party on Glasgow City Council after decades of Labour control.
In January 2018, the council said it hoped to resolve the dispute through negotiation. But union members, angry at a lack of progress, said earlier this month they would strike.
How many workers are affected?
As many as 12,000 people are making equal pay claims, some of them dating back 12 years.
The biggest group are represented by the campaign group Action 4 Equality Scotland.
It is thought it could cost hundreds of millions of pounds to settle.
More than 8,000 members of the GMB and Unison unions are said to be taking part in the 48-hour industrial action.