The 1986 Belgian Grand Prix was a Formula One motor race held at the Circuit de Spa-Francorchamps on 25 May 1986. It was the fifth race of the 1986 FIA Formula One World Championship. The race was the 44th Belgian Grand Prix and the 32nd to be held at Spa-Francorchamps. It was held over 43 laps of the circuit for a total race distance of .
The race was won by British driver Nigel Mansell, driving a Williams-Honda. It was Mansell's first victory of the season. Brazilian driver Ayrton Senna finished second in a Lotus-Renault, with Sweden's Stefan Johansson third in a Ferrari. Senna's result allowed him to take the lead of the Drivers' Championship from Frenchman Alain Prost, who could only manage sixth in his McLaren-TAG.
Qualifying
Brabham entered only one BT55, the car of Riccardo Patrese. Elio de Angelis had been killed in a testing accident at Circuit Paul Ricard just over a week before the race. Williams-Honda driver Nelson Piquet took pole late in the qualifying session using the team's spare car. Piquet's engine blew up in his race car during qualifying forcing him into the spare. Austrian Gerhard Berger scored his first front row start and the first for the BMW powered Benetton after being fastest in Friday qualifying. His Friday time of 1:54.468 was half a second faster than his Saturday time but still good enough for the front row. falling back to 4th place. Piquet led until suffering turbo failure on lap 16, leaving Senna in front, ahead of Mansell, who shortly overtook Senna during pit stops. Prost emerged last on the road and only a few hundred metres in front of the leading Williams, on his way to being the last car on the lead lap and finishing in sixth place. He set a new lap record of 1:59.282 on lap 31.
Nigel Mansell scored his first win of 1986 and the third win of his career. Senna, the cause of the first corner crash, finished 20 seconds behind in second, with Stefan Johansson finishing third after passing team leader Alboreto only two laps from home. Jacques Laffite finished fifth in his Ligier-Renault with Prost gaining a vital World Championship point for finishing sixth. Swiss driver Marc Surer finished ninth in his Arrows A8 in what would be the last Grand Prix of Surer's career – he would be seriously injured competing in the European Rally Championship a week later. Post race, Mansell dedicated his win to his friend and former team mate Elio de Angelis, who died just ten days prior to Spa in a testing accident at Paul Ricard.
Classification
Qualifying
{| class="wikitable sortable" style="font-size: 95%;"
|-
! Pos !! No !! Driver !! Constructor !! Q1 !! Q2 !! Gap
|-
! 1
| 6
| Nelson Piquet
| Williams-Honda
| 1:54.637
| 1:54.331
|align="center"| —
|-
! 2
| 20
| Gerhard Berger
| Benetton-BMW
| 1:54.468
| 1:54.939
| +0.137
|-
! 3
| 1
| Alain Prost
| McLaren-TAG
| 1:55.039
| 1:54.501
| +0.170
|-
! 4
| 12
| Ayrton Senna
| Lotus-Renault
| 1:55.776
| 1:54.576
| +0.245
|-
! 5
| 5
| Nigel Mansell
| Williams-Honda
| 1:55.345
| 1:54.582
| +0.251
|-
! 6
| 19
| Teo Fabi
| Benetton-BMW
| 1:57.440
| 1:54.765
| +0.434
|-
! 7
| 25
| René Arnoux
| Ligier-Renault
| 1:57.269
| 1:55.576
| +1.245
|-
! 8
| 2
| Keke Rosberg
| McLaren-TAG
| 1:56.534
| 1:55.662
| +1.331
|-
! 9
| 27
| Michele Alboreto
| Ferrari
| 1:56.294
| 1:56.242
| +1.911
|-
! 10
| 16
| Patrick Tambay
| Lola-Ford
| 1:58.574
| 1:56.309
| +1.978
|-
! 11
| 28
| Stefan Johansson
| Ferrari
| 1:57.697
| 1:56.496
| +2.165
|-
! 12
| 3
| Martin Brundle
| Tyrrell-Renault
| 1:57.797
| 1:56.537
| +2.206
|-
! 13
| 11
| Johnny Dumfries
| Lotus-Renault
| 1:58.619
| 1:57.462
| +3.131
|-
! 14
| 18
| Thierry Boutsen
| Arrows-BMW
| 1:57.918
| 1:57.612
| +3.281
|-
! 15
| 7
| Riccardo Patrese
| Brabham-BMW
| 2:00.357
| 1:57.612
| +3.281
|-
! 16
| 15
| Alan Jones
| Lola-Ford
| 1:59.180
| 1:57.815
| +3.484
|-
! 17
| 26
| Jacques Laffite
| Ligier-Renault
| 1:58.238
| 2:27.817
| +3.907
|-
! 18
| 4
| Philippe Streiff
| Tyrrell-Renault
| 1:59.347
| 1:58.603
| +4.272
|-
! 19
| 23
| Andrea de Cesaris
| Minardi-Motori Moderni
| 2:00.984
| 1:59.960
| +5.629
|-
! 20
| 14
| Jonathan Palmer
| Zakspeed
| 2:02.307
| 2:00.148
| +5.817
|-
! 21
| 17
| Marc Surer
| Arrows-BMW
| 2:01.320
| 2:01.415
| +4.661
|-
! 22
| 24
| Alessandro Nannini
| Minardi-Motori Moderni
| 2:01.528
| 2:01.354
| +7.023
|-
! 23
| 29
| Huub Rothengatter
| Zakspeed
| 2:06.006
| 2:03.842
| +9.511
|-
! 24
| 21
| Piercarlo Ghinzani
| Osella-Alfa Romeo
| 2:05.092
| 3:38.767
| +10.761
|-
! 25
| 22
| Christian Danner
| Osella-Alfa Romeo
| 2:09.465
| 2:06.219
| +11.888
|}
Race
{| class="wikitable" style="font-size: 95%;"
|-
! Pos !! No !! Driver !! Constructor !! Laps !! Time/Retired !! Grid !! Points
|-
! 1
| 5
| Nigel Mansell
| Williams-Honda
| 43
| 1:27:57.925
| 5
| 9
|-
! 2
| 12
| Ayrton Senna
| Lotus-Renault
| 43
| + 19.827
| 4
| 6
|-
! 3
| 28
| Stefan Johansson
| Ferrari
| 43
| + 23.592
| 11
| 4
|-
! 4
| 27
| Michele Alboreto
| Ferrari
| 43
| + 29.634
| 9
| 3
|-
! 5
| 26
| Jacques Laffite
| Ligier-Renault
| 43
| + 1:10.690
| 17
| 2
|-
! 6
| 1
| Alain Prost
| McLaren-TAG
| 43
| + 2:17.772
| 3
| 1
|-
! 7
| 19
| Teo Fabi
| Benetton-BMW
| 42
| + 1 Lap
| 6
|
|-
! 8
| 7
| Riccardo Patrese
| Brabham-BMW
| 42
| + 1 Lap
| 15
|
|-
! 9
| 17
| Marc Surer
| Arrows-BMW
| 41
| + 2 Laps
| 21
|
|-
! 10
| 20
| Gerhard Berger
| Benetton-BMW
| 41
| + 2 Laps
| 2
|
|-
! 11
| 15
| Alan Jones
| Lola-Ford
| 40
| Out of Fuel
| 16
|
|-
! 12
| 4
| Philippe Streiff
| Tyrrell-Renault
| 40
| + 3 Laps
| 18
|
|-
! 13
| 14
| Jonathan Palmer
| Zakspeed
| 37
| + 6 Laps
| 20
|
|-
!
| 23
| Andrea de Cesaris
| Minardi-Motori Moderni
| 35
| Out of Fuel
| 19
|
|-
!
| 29
| Huub Rothengatter
| Zakspeed
| 25
| Electrical
| 23
|
|-
!
| 3
| Martin Brundle
| Tyrrell-Renault
| 25
| Gearbox
| 12
|
|-
!
| 24
| Alessandro Nannini
| Minardi-Motori Moderni
| 24
| Gearbox
| 22
|
|-
!
| 25
| René Arnoux
| Ligier-Renault
| 23
| Engine
| 7
|
|-
!
| 6
| Nelson Piquet
| Williams-Honda
| 16
| Turbo
| 1
|
|-
!
| 18
| Thierry Boutsen
| Arrows-BMW
| 7
| Electrical
| 14
|
|-
!
| 11
| Johnny Dumfries
| Lotus-Renault
| 7
| Spun Off
| 13
|
|-
!
| 2
| Keke Rosberg
| McLaren-TAG
| 6
| Engine
| 8
|
|-
!
| 21
| Piercarlo Ghinzani
| Osella-Alfa Romeo
| 3
| Engine
| 24
|
|-
!
| 22
| Christian Danner
| Osella-Alfa Romeo
| 2
| Engine
| 25
|
|-
!
| 16
| Patrick Tambay
| Lola-Ford
| 0
| Accident
| 10
|
|-
!colspan="8"|
|}
Championship standings after the race
;Drivers' Championship standings
{| class="wikitable" style="font-size: 95%;"
|-
!Pos
!Driver
!Points
|-
| 1
| Ayrton Senna
| align="right"| 25
|-
| 2
| Alain Prost
| align="right"| 23
|-
| 3
| Nigel Mansell
| align="right"| 18
|-
| 4
| Nelson Piquet
| align="right"| 15
|-
| 5
| Keke Rosberg
| align="right"| 11
|-
!colspan=4|Source:
|}
;Constructors' Championship standings
{|class="wikitable" style="font-size: 95%;"
|-
! Pos
! Constructor
! Points
|-
| 1
| McLaren-TAG
| align="right"|34
|-
| 2
| Williams-Honda
| align="right"|33
|-
| 3
| Lotus-Renault
| align="right"|25
|-
| 4
| Ligier-Renault
| align="right"|12
|-
| 5
| Ferrari
| align="right"|10
|-
!colspan=4|Source: