Its mission is to define and implement policies that promote the development of the Municipality in different areas.
Its powers and legal regime are enshrined in the Local Authorities Law
The municipalities have powers in the fields of social action; environment; communications; external cooperation; culture and science; consumer protection; sports; education; energy; rural and urban equipment; housing; spatial planning and urbanism; heritage; municipal police; promotion of development; civil protection; basic sanitation; health; leisure; and transport.
The Lisbon administrative reform, enshrined in Law 56/2012 reduced the number of parishes - from 53 to 24 -, with more resources and new powers.
The principles of administrative decentralisation and subsidiarity, were realised through a process of decentralisation between local authorities, providing increasing articulation and cooperation between the municipality and the parishes.