Former president Nelson Mandela has been ranked first in a perception assessment of 54 of the world's most visible leaders, according to the Reputation Institute on Wednesday.
President Jacob Zuma came 35th, behind the likes of actress Angelina Jolie (12th), the institute said in a statement.
The Dalai Lama was ranked 13th, US president Barack Obama 14th, Facebook founder Mark Zuckerberg 20th, footballer David Beckham (24th), the Pope (26th), Prince Albert of Monaco (28th), and Madonna(29th).
Zuma beat Wikileaks founder Julian Assange (37th), entertainer Lady Gaga (41st), Hugo Chavez, president of Venezuela (49th), George W Bush (50th) and Cuban leader Fidel Castro (51st).
Mandela, who has retired to his home in the Eastern Cape, beat tennis star Roger Federer, who came second.
Just over 51 000 members of the general public in 25 countries were asked to assess these individuals using the institute's "RepTrak Pulse" to measure their reputation on a 0-100 point scale based on four attributes in April-May 2011.
These were: the degree to which a person is liked, respected, admired, and trusted.
The institute said Mandela's powerful story of offender to beloved first president of South Africa had made him a symbol of the worldwide struggle against injustice.
He was a continuing source of inspiration to people the world over, the institute commented.
Federer, a five-time US Open tennis champion, was admired as much for his on-court results as for his off-court charitable efforts.
Like Mandela, Federer had a passion for South Africa and its people, "due no doubt to his mother's heritage", the institute said. (Federer's mother, Lynette, is South African. His father, Robert, is Swiss).
Business "visionaries" ranked high on the list, and included Microsoft's Bill Gates (3rd), investor Warren Buffet (4th), music and airline mogul Richard Branson (5th), Apple innovator Steve Jobs (6th), and India's Ratan Tata (7th), CEO of the Tata group.
Social entrepreneurs Oprah Winfrey (8th) and U2's Bono (9th) regularly called public attention to global causes for which they earned high praise from the public.
At the other extreme, the public gave its weakest ratings to leaders deemed "anti-democratic".
Kim Jong-il, of North Korea, took last place in the study.
Trophy-rich golfer Tiger Woods also sat near the end of the list.
"The results of Reputation Institute's study confirmed that people respect leaders that participate in philanthropic activities outside of their own celebrity."