In a desperately poor game, Kayode Odejayi scored the only goal of the game on the stroke of half time to inflict a 10th home defeat of the campaign on the Grecians.
Accrington edged a scrappy first half and had gone close a few times before they eventually broke the deadlock just before the break.
Adam Buxton saw a shot deflect just wide and Lee Molyneux was also off target, but when the opening goal came, there was a sense of fortune.
Exeter could not clear Molyneux's corner kick and after a scramble in the six-yard box, Odejayi bundled the ball over the line.
The second half was little better in terms of quality, although Exeter were marginally better than they had been in the first. But despite enjoying the lions' share of possession, they failed to test visiting goalkeeper Marcus Bettinelli.
Liam Sercombe's 90th minute free-kick was as good as it got for them, while Accrington also failed to register an effort of note in a poor game of football.