Fast-growing municipalities are communities experiencing rapid population growth and development that creates intense pressure on infrastructure, services, and planning systems. These municipalities face distinct challenges: infrastructure must be built ahead of or alongside development, development charges and tax revenue lag behind service demands, land use conflicts intensify as development meets established areas, and organizational capacity struggles to keep pace with approval volumes. Some provinces designate fast-growing municipalities for special attention, providing additional planning resources, modified regulations, or priority infrastructure funding. Examples include communities in the Greater Golden Horseshoe around Toronto, Calgary and Edmonton metropolitan regions, and communities in British Columbia's Lower Mainland. Managing growth while maintaining livability, affordability, and fiscal sustainability requires sophisticated planning, adequate funding tools, and often provincial partnership.