More than 100 elected officials from throughout California, including more than 20 from the Inland Empire, have formally declared their opposition to Proposition 21.
The list includes county supervisors, mayors, city council members, city clerks, and board members, according to a statement.
If passed, Prop. 21 would allow local governments to enact rent control on housing that was first occupied more than 15 years ago. Some exceptions would be landlords who own no more than two homes.
Foes of the measure say it will reduce affordable housing statewide and require cuts in community services.
San Bernardino County Supervisor Curt Hagman, Riverside County Supervisor Kevin Jeffries, Ontario Councilman Alan Wapner, and Hemet Councilwoman Karlee Meyer are among the Inland officials against Prop. 21.