| Election Name: | 1978 French legislative election |
| Country: | France |
| Type: | legislative |
| Ongoing: | no |
| Previous Election: | 1973 French legislative election |
| Previous Year: | 1973 |
| Next Election: | 1981 French legislative election |
| Next Year: | 1981 |
| Seats For Election: | All 491 seats to the French National Assembly 246 seats were needed for a majority |
| Election Date: | 12 and 19 March 1978 |
| Turnout: | 82.8% (1.6 pp) (1st round) 84.7% (1.9 pp) (2nd round) |
| Leader1: | Jacques Chirac |
| Party1: | Rally for the Republic |
| Leaders Seat1: | Corrèze-3rd |
| Last Election1: | 183 seats (UDR) |
| Seats1: | 150 |
| Seat Change1: | 33 |
| Popular Vote1: | 6,462,462 (round) 6,651,756 (round) |
| Percentage1: | 22.62% (round) 26.11% (round) |
| Leader4: | François Mitterrand |
| Party4: | Socialist Party (France) |
| Leaders Seat4: | Nièvre-3rd |
| Last Election4: | 102 seats |
| Seats4: | 104 |
| Seat Change4: | 2 |
| Popular Vote4: | 6,451,151 (round) 7,212,916 (round) |
| Percentage4: | 22.58% (round) 28.31% (round) |
| Leader2: | Jean Lecanuet |
| Party2: | Union for French Democracy |
| Leaders Seat2: | Seine-Maritime (Senator) |
| Last Election2: | 119 seats (Reforming Movement, Centre, Democracy and Progress, and Independent Republicans) |
| Seats2: | 121 |
| Seat Change2: | 2 |
| Popular Vote2: | 6,128,849 (1st round) 5,907,603 (2nd round) |
| Percentage2: | 21.45% (1st round) 23.18% (2nd round) |
| Leader5: | Georges Marchais |
| Party5: | French Communist Party |
| Leaders Seat5: | none |
| Last Election5: | 73 seats |
| Seats5: | 86 |
| Seat Change5: | 13 |
| Popular Vote5: | 5,870,402 (1st round) 4,744,868 (2nd round) |
| Percentage5: | 20.55% (1st round) 18.62% (2nd round) |
| Prime Minister | |
| Before Election: | Raymond Barre |
| Before Party: | Union for French Democracy |
| After Election: | Raymond Barre |
| After Party: | Union for French Democracy |
Legislative elections were held in France on 12 and 19 March 1978 to elect the sixth National Assembly of the Fifth Republic. On 2 April 1974, President Georges Pompidou died. The non-Gaullist centre-right leader Valéry Giscard d'Estaing was elected to succeed him. Because the Gaullist Union of Democrats for the Republic (Union des démocrates pour la République, UDR) was the largest party in the pro-Giscard majority in the Assembly, Giscard chose Jacques Chirac to lead the cabinet. This period was one of renovation for Gaullism.
The presidential will to "govern towards the centre" and to promote a "modern liberal society" disconcerted the Gaullist party. The Abortion Act and the reduction of the age of majority to 18 years worried a part of the conservative electorate. Furthermore, a personal conflict opposed the two heads of the executive. In August 1976, Chirac resigned because he considered that he did not have "the means to carry on [his] function of Prime Minister".
Three months later, the UDR was replaced by the Rally for the Republic (Rassemblement pour la République, RPR). This, Chirac's electoral machine, was officially a member of the Presidential Majority but frequently criticized the liberal and pro-European policy of President Giscard d'Estaing and his new prime minister Raymond Barre. The executive duo reacted by federating the non-Gaullist centre-right in the Union for French Democracy (Union pour la démocratie française, UDF).
While the right-wing majority was divided and the economic situation deteriorated, the "Union of the Left" won the mid-term local elections. According to the polls, it was the favourite to win the legislative election. In his Verdun-sur-le-Doubs speech, President Giscard d'Estaing warned the French voters that he could not prevent the enforcement of the left-wing Common programme if the "Union of the Left" won. The Socialist Party (Parti socialiste, PS) and the French Communist Party (Parti communiste français, PCF) did not update their Common programme due to increasing tension between the two parties resulting from the PS gaining in electoral success at the PCF's expense.
For the first time since 1936, the Socialists obtained more votes than the Communists. Furthermore, the French electorate appeared evenly shared between four equivalent political parties (RPR, UDF, PS, PCF). Barre was confirmed as Prime Minister. Until the 2007 French legislative election, it was the last time that either the right or the left had won back-to-back legislative elections.