Le Guen’s most successful stint as manager was at Olympique Lyonnais. He won four consecutive Ligue 1 titles. He resigned on May 9th, 2005 – a day after winning the fourth title.
He qualified Cameroon for the 2010 World Cup in South Africa. Cameroon were the first team to be knocked out of the competition. He announced his resignation on 24 June, 2010.
He joined Oman on 11 June, 2011. He led the team to qualify for the 2015 AFC Asian Cup. Oman were eliminated in the group stage of the tournament with one win and two losses. He was relieved of his position on 19 November, 2015.