Mr Chandy bagged the first prize from the Asia Pacific region with awardees chosen every year from five zones around the world, a release from the Chief Minister's office said.
Since 2003, UN has been giving the award as part of its programme for Public Service Day, which is observed on June 23.
The awards, instituted through a UN resolution, are announced after a three-tier scrutiny and detailed examination.
The shortlisted candidates are examined by a seven-member sub-committee of UN's Committee of Experts in Public Administration.
This year, UN Public Service Day ceremonies will be held from June 24 to 27 in Bahrain where UN Secretary-General Ban Ki-Moon will distribute the awards on June 27. Mr Chandy would be attending the meet to receive his award on that day.
Mr Chandy's mass contact programme has been widely lauded as a unique democratic experiment in which the Chief Minister of an Indian state met thousands of people directly without any intermediaries.
He received upto 5.5 lakh petitions, of which around 3 lakh were resolved, and distributed financial assistance of Rs 22.68 crore as part of the programme.
Evaluation criteria for the awards include transparency, mechanisms to increase public's ability to seek and receive information in a timely manner and monitoring and analysing government decision-making and processes.
Promotion of accountability and documentation, which can serve as evidence of a government's conformity to legal, procedural and fiscal requirements, were also among the parameters.