| Club: | Dumbarton |
| Season: | 1986–1987 |
| Manager: | Alex Totten |
| Stadium: | Boghead Park, Dumbarton |
| League: | Scottish League Division 1 |
| League Result: | 3rd |
| Cup1: | Scottish Cup |
| Cup1 Result: | Third Round |
| Cup2: | Scottish League Cup |
| Cup2 Result: | Third Round |
| Matches: | 48 |
| Total Goals: | 72 |
| League Topscorer: | Gerry McCoy (21) |
| Season Topscorer: | Gerry McCoy (22) |
| Highest Attendance: | 2,500 |
| Lowest Attendance: | 440 |
| Average Attendance: | 1,180 |
| Prevseason: | 1985–86 |
| Nextseason: | 1987–88 |
Season 1986–87 was the 103rd football season in which Dumbarton competed at a Scottish national level, entering the Scottish Football League for the 81st time, the Scottish Cup for the 92nd time and the Scottish League Cup for the 40th time.
Dumbarton began another First Division campaign with a new manager at the helm - Alex Totten - who had been released from his duties with Rangers following the arrival of Graeme Souness. Following another league reconstruction, the First Division clubs would play each other 4 times - a big ask particularly for the part-time clubs - but as things turned out it was to be a close thing for promotion with Dumbarton always up with the front runners. In the end, it was to be a 3rd-place finish - just 4 points behind champions Morton.
In the Scottish Cup, it would be another early exit for Dumbarton, this time to Brechin City after a draw, in the third round.
In the League Cup, Stirling Albion were dispatched in the second round before a fighting display against Celtic, saw Dumbarton's interest in the competition come to an end for another year.
Locally, Dumbarton failed to keep a grip on the Stirlingshire Cup, with Stirling Albion gaining some revenge for their League Cup exit, with a semi final win.
See main article: 1986-87 Scottish First Division.
See main article: 1986-87 Scottish League Cup.
See main article: 1986–87 Scottish Cup.
Owen Coyle was selected to play for the Republic of Ireland Under 21 team in matches against Scotland on 17 February played at Easter Road and against Belgium on 28 April.
| Player | From | Date | |
|---|---|---|---|
| Arthur Grant | Stenhousemuir | 9 Aug 1986 | |
| Peter Houston | Falkirk | 16 Aug 1986 | |
| Dave Martin | Alloa Athletic | 20 Sep 1986 | |
| Billy Traynor | Belhaven Athletic | 6 Nov 1986 | |
| Jim Rooney | St Mirren | 8 Nov 1986 | |
| Joe McLeod | Dundee Utd (loan) | 16 Feb 1987 | |
| Jim McNeil | Vale of Clyde | 28 Mar 1987 |
| Player | To | Date | |
|---|---|---|---|
| Martin McGowan | Stranraer | 24 May 1986 | |
| Gerry Crawley | Brechin City | 5 Jul 1986 | |
| Mark Shanks | Queen of the South | 12 Jul 1986 | |
| Paul Taylor | Berwick Rangers | 26 Jul 1986 | |
| Albert Craig | Hamilton | 16 Aug 1986 | |
| John Bourke | Brechin City | 1 Nov 1986 | |
| Allan Moore | Hearts | 15 Nov 1986 | |
| Harry Curran | Dundee United | 28 Feb 1987 | |
| Ken Thomson | Kilbirnie Ladeside |
Dumbarton competed in the Scottish Reserve League (West).