Who Is The Longest Serving Prime Minister In The World?

Who Is The Longest Serving Prime Minister In The World? Rank Name Office 1.Paul Biya Prime Minister, then President 2. Teodoro Obiang Nguema Mbasogo President 3. Ali Khamenei President, then Supreme Leader 4. Denis Sassou Nguesso President Who is the longest serving prime minister? Rank Prime Minister Length served 1Sir Robert Walpole20 years, 314 days