The Head of Government of Papua New Guinea is a Prime Minister, a member of Parliament who is elected by a majority vote in Parliament following national elections or after a vacancy has arisen (for example due to a vote of no confidence). Following national elections, the leader of the party who has won the largest number of seats is invited by the Governor-General to nominate for the position. If he or she fails to receive a majority of votes, other candidates can be nominated for the position.
Prime Ministers are regularly threatened with votes of no confidence under which they can be removed by a simple majority of those voting. The constitutional provision for parliamentary votes of no confidence has created instability because no party has been able to muster sufficient votes to govern in its own right. All governments have been fragile coalitions. There have been 15 votes of no-confidence since 1975. Michael Somare was removed by votes of no confidence in March 1980 and November 1985, and Paias Wingti in July 1988. In July 1991 the Constitution was amended to extend from 6 to 18 months the period in which a newly elected Government is free from an Opposition no-confidence motion.
List of Prime Ministers of Papua New Guinea
| Name | Tenure | Political Affiliation |
| Michael Somare | 1975-1980 | Pangu Party |
| Sir Julius Chan | 1980-1982 | People’s Progress Party |
| Michael Somare | 1982-1985 | Pangu Party |
| Paias Wingti | 1985-1988 | People’s Democratic Movement |
| Sir Rabbie Namaliu | 1988-1992 | Pangu Party |
| Paias Wingti | 1990-1994 | People’s Democratic Movement |
| Sir Julius Chan | 1994-1997 | People’s Progress Party |
| John Giheno (Acting) | 1997 | People’s Progress Party |
| Sir Julius Chan | 1997 | People’s Progress Party |
| Bill Skate | 1997-1999 | People’s National Congress Party |
| Sir Mekere Morauta | 1999-2002 | People’s Democratic Movement |
| Sir Michael Somare | 2002-2011 | National Alliance Party |
| Sam Abal (Acting) | 2010-2011 | National Alliance Party |
| Peter O’Neill | 2011-Now | People’s National Congress Party |