| Country: | Iceland |
| Previous Election: | 1983 |
| Election Date: | 25 April 1987 |
| Next Election: | 1991 |
| Seats For Election: | All 42 seats in the Lower House and 21 seats in the Upper House of Althing |
| Turnout: | 90.10% |
| Heading1: | Upper House |
| Heading7: | Lower House |
| Leader1: | Þorsteinn Pálsson |
| Leader7: | Þorsteinn Pálsson |
| Party1: | Independence Party (Iceland) |
| Party7: | Independence Party (Iceland) |
| Last Election1: | 8 |
| Last Election7: | 15 |
| Seats1: | 6 |
| Seats7: | 12 |
| Percentage1: | 27.17 |
| Percentage7: | 27.17 |
| Leader8: | Steingrímur Hermannsson |
| Party2: | Progressive Party (Iceland) |
| Party8: | Progressive Party (Iceland) |
| Last Election2: | 4 |
| Last Election8: | 10 |
| Seats2: | 5 |
| Seats8: | 8 |
| Percentage2: | 18.92 |
| Percentage8: | 18.92 |
| Leader3: | Jón Baldvin Hannibalsson |
| Leader9: | Jón Baldvin Hannibalsson |
| Party3: | Social Democratic Party (Iceland) |
| Party9: | Social Democratic Party (Iceland) |
| Last Election3: | 2 |
| Last Election9: | 4 |
| Seats3: | 3 |
| Seats9: | 7 |
| Percentage3: | 15.23 |
| Percentage9: | 15.23 |
| Leader4: | Svavar Gestsson |
| Leader10: | Svavar Gestsson |
| Party4: | People's Alliance (Iceland) |
| Party10: | People's Alliance (Iceland) |
| Last Election4: | 3 |
| Last Election10: | 7 |
| Seats4: | 3 |
| Seats10: | 5 |
| Percentage4: | 13.35 |
| Percentage10: | 13.35 |
| Leader5: | Albert Guðmundsson |
| Leader11: | Albert Guðmundsson |
| Party5: | Citizens' Party (Iceland, 1987) |
| Party11: | Citizens' Party (Iceland, 1987) |
| Last Election5: | new |
| Last Election11: | new |
| Seats5: | 2 |
| Seats11: | 5 |
| Percentage5: | 10.86 |
| Percentage11: | 10.86 |
| Party6: | Women's List |
| Party12: | Women's List |
| Last Election6: | 1 |
| Last Election12: | 2 |
| Seats6: | 2 |
| Seats12: | 4 |
| Percentage6: | 10.13 |
| Percentage12: | 10.13 |
| Leader13: | Stefán Valgeirsson |
| Party13: | Association for Justice and Equality |
| Last Election13: | new |
| Seats13: | 1 |
| Percentage13: | 1.24 |
| Prime Minister | |
| Before Election: | Steingrímur Hermannsson |
| Before Party: | Progressive Party (Iceland) |
| After Party: | Independence Party (Iceland) |
Parliamentary elections were held in Iceland on 25 April 1987.[1] The Independence Party remained the largest party in the Lower House of the Althing, winning 12 of the 42 seats.[2]
Prior to the election three extra seats were added to the Althing for Reykjavík (increasing representation from 11 to 14),[3] one in the Upper House and two in the Lower House.[4] The Hare quota replaced the D'Hondt method in the multi-member constituencies, although D'Hondt was still used for the compensatory seats.[3]
Four constituencies elected five members each, two elected six members each, and one elected eight members, while Reykjavík elected 14. At least eight of the remaining nine seats were to be allocated to the constituencies before the election in order to reflect population. One seat could be allocated after the election, in order to help ensure proportionality across parties. A party threshold was introduced at the constituency level at two-thirds of a Hare quota; seats were eliminated one at a time and the threshold was then recalculated.[5]