Federal regulations affecting municipalities are rules established under federal jurisdiction that local governments must comply with despite municipalities being constitutionally provincial responsibilities. Key areas include: environmental regulations (wastewater effluent limits, air quality standards, species at risk), building accessibility (Canadian Human Rights Act, Accessible Canada Act), labour standards for federally-regulated workplaces, transportation rules for international and interprovincial movement, food safety in certain facilities, and communications infrastructure regulations. Municipalities don't choose whether to comply—federal law applies regardless of provincial or local preferences. Compliance can be costly, as when wastewater regulations require treatment plant upgrades. Municipalities have limited input into federal regulation-making despite bearing implementation costs. Federal regulatory changes can disrupt municipal plans and budgets. Understanding which federal regulations apply helps municipalities plan compliance and advocate for reasonable implementation timelines and support.