The LMA represents all managers and former managers of clubs in the English Premier and Football Leagues.
The Nottingham-based football and sports PR company will act as the exclusive agency to promote the activities of the LMA.
Macesport will be responsible for delivering a programme to strengthen working relationships with all sections of the media, provide specialist media relations advice and establish a media helpline service for all managers.
LMA chief executive John Barnwell said: “The LMA has grown significantly in recent years and this appointment will enable us to further develop our profile."
Macesport managing director Paul Mace said: “In the 13 years since its inception, the LMA has established itself as a major representative voice in English football.
“Our brief will be to further promote the considerable activities of the LMA and offer expert advice, assistance and support to its members in relation to the ever-increasing media demands placed on them.”
