Moments of quality were at a real premium in this contest, but the Rebels had the better of the play against their playoff-chasing opponents and deserved the win overall.
Eddie Smith went closest as Slough created openings in the first half, hitting the underside of the crossbar in the 25th minute after turning smartly in the box.
Smith hit another effort over after Ryan Hope clipped a pass across to him, whilst Warren Harris fired over and Jhai Dhillon forced a save at the near post from Jamie Head after a deep cross from the Slough right winger.
Dunstable created half-chances but were off target with most of them. Danny Talbot put a shot over the bar and later hit a 30-yard free kick which Mark Scott gathered easily.
Five minutes before the interval, a Dunstable defender got a touch to Lewis Putman's corner and flicked the ball all the way across goal, which almost snuck in at the far post but clipped the woodwork and went wide.
Dunstable struggled to create chances against a resolute, solid Slough, with Guy Hollis particularly impressive. Adam Watkins dragged a shot well wide from 18 yards in a rare attack at the start of the second half.
The game looked to be heading for a stalemate as the second half progressed, with Slough looking the more likely to break the deadlock. Dhillon fired into the side netting and substitute Lee Barney saw an effort saved a minute after entering the fray.
But with eight minutes left, Guy Hollis was dragged to the ground by David Longe-King as a free kick was played into the box, and the resulting award of a penalty gave Smith the chance to become the club's joint 10th highest goalscorer of all time with 95 goals for the club. Dunstable keeper Jamie Head will be disappointed as the spot-kick was blasted straight through him, but it was confidently dispatched by the Rebels striker.
Two minutes from time, Barney tried to beat Head at his near post, but the keeper was able to turn it behind; and Warren Harris blazed over in stoppage time as Slough looked to wrap it up.
Deep into stoppage time, Dunstable almost forced an unlikely equaliser, but a header was straight at Mark Scott and Slough secured all three points.
Dunstable Town Line up
Jamie Head, Howard Hall, Zack Reynolds, Daniel Talbot, Jamie Kaloczi (c), Adam Pepera, Adam Watkins, Daniel Longe-King, Lee Roache (Connor Calcutt), David Keenleyside (Steve Wales), Gary Wharton (Chris Vardy). Subs not used: Steve Wake, Tony Fontenelle.