In a sign of growing unrest in another Massachusetts school district, this time its largest, the Boston Teachers Union plans Thursday to hold informational pickets before school begins at all 116 public schools in the city.

The union voted unanimously Jan. 8 to hold the citywide pickets, saying its vote reflected frustration after nearly a year of contract talks with city leaders failed to "yield meaningful progress on critical issues."

Educators on Thursday "will still report to school and carry out their duties as normal," the union said.

"Our members have spoken loud and clear: we are united in our fight for a contract that prioritizes students and respects educators," BTU President Erik Berg said. "This unanimous vote shows the collective strength of our union and the urgency of our demands. We are ready to take action to push the district and the City to do what’s right for Boston’s students and educators."

Teachers in several school districts have staged illegal strikes in recent years, disrupting schools and drawing fines but leading to contract agreements.

In Boston, the union says it wants "fair wages for educators and paraprofessionals and fully staffed classrooms that meet the needs of all students, including those with disabilities and English language learners." The BTU said current practices in the district "are unsustainable and detrimental to students’ success."

The pickets are set to unfold at the start of a mayoral election year in Boston.