Joan Clos i Matheu, GCIH (Catalan pronunciation: [?u'a? 'kl?s]; born 29 June 1949) is a Spanish politician who was mayor of Barcelona, Spain from September 1997 to September 2006.
He took over from Pasqual Maragall in 1997.
In 1999 he was elected to a four-year term, and was then re-elected in the municipal elections of 25 May 2003.
After a stint as the Spanish Ambassador in Turkey and Azerbaijan, in 2010 he was appointed as Executive Director of the United Nations Human Settlements Programme, (UN-HABITAT), and Under Secretary General of the United Nations.