A Catholic lay association, also referred to as Catholic Congress, is an association of lay Catholics aiming to discuss certain political or social issues from a Catholic perspective.
There are many thousands of lay associations existing at a local, diocesan, national / bishops conference or international level. The cover the whole spectrum of Catholic Lay life, from their Faith, Social Action, to the Professions in which they work.
The majority have sought and have been given backing by the appropriate "ecclesiastical authority". However, others have invoked the right contained in Canon 215 to form a Catholic Association without ecclesiastical approval. In these circumstances the only prescription on them is that they cannot use the term "Catholic" in their name. (Can. 216)
The Pontifical Council for the Laity is the body responsible for approving those Catholic Associations that exist at an international level. The structure of some Religious Orders allow for Lay branches to be associated with them. These are often referred to as Third Orders.
Some of the best known Catholic Lay Associations are Knights of Columbus, Knights of Columba, Catenians, Knights of Malta, the Piusverein in Germany and Switzerland, Azione Cattolica in Italy and the UK-based Catholic Truth Society.
There are also many lay Catholic guilds and associations representing a whole range of professions. These include the Catholic Police Guild, Holy Name Society (NYPD), the Association of Catholic Nurses, the Guild of Catholic Doctors, the Catholic Phyicians Guild, the Catholic Association of Performing Arts (UK), the Catholic Actors Guild of America.