Lolley's deflected effort, his eighth of the campaign, was the difference between the two promotion chasers in West London as The Reds moved to within just two points of the automatic promotion places.
Sabri Lamouchi made just one change from the last week's draw against Reading for their visit to the capital. Tobias Figueiredo came back into the side in place of Michael Dawson at the heart of the Forest defence, taking his spot alongside Joe Worrall.
The opening ten minutes were played at a frantic pace, very similar to a cup tie, with both sides looking to get the early advantage.
Lewis Grabban and Lolley were threatening the hosts on the break at every opportunity and it was the latter who found the early breakthrough. Tiago Silva's corner was only partially cleared and the ball fell to an unmarked Lolley on the edge of the area and his deflected shot sailed over David Raya in the Brentford goal to put the visitors in front with 14 minutes on the clock.
Despite going behind, Brentford still looked lively in possession and nearly found themselves level ten minutes later. Ollie Watkins raced clear for The Bees but dragged his left-footed effort wide of Brice Samba's goal.
As the half wore on, Forest looked content with letting Brentford have the ball and the hosts' frustrations were beginning to show. Winger Said Benrahma seemingly kicked out at Samba Sow deep inside the Forest half and was shown a yellow card when it looked as if the punishment could have been worse.
The visitors remained composed and despite a flurry of set-pieces from the hosts towards the end of the first half, they held onto their one goal advantage going into the break.
Brentford began the second half piling pressure on the Forest goal with multiple crosses and neat passing in and around the penalty area but were failing to create any clear-cut chances.
The visitors on the other hand were looking dangerous with every attack as they went in search of a second and it nearly came through Grabban. A loose ball fell to the leading goalscorer in the hosts' penalty box, however he could only direct his shot straight at Raya.
The striker was causing the home side all sorts of problems and should have had a penalty just after the hour mark. After a long ball over the top from Cash was chased down by Grabban, the Brentford defender Ethan Pinnock climbed all over the back of the Forest man to prevent him being through on goal but referee Tim Robinson adjudged the tackle to be fair and waved play on.
With just 15 minutes left on the clock the visitors made their first change of the match with Lolley being replaced by Adama Diakhaby who was making his debut after joining the club on loan from Huddersfield.
As the match entered the final ten minutes, Forest were still looking for the all-important second goal and it nearly came through Ameobi. The former Bolton man deflected a cross from Silva towards the near post but it was bundled wide for a corner to the visitors.
The home side were not out of it yet though and nearly found an equaliser through substitute Emiliano Marcondes. The Brentford man hit a sweet set-piece from the edge of the area that was dropping in, however Samba managed to tip the effort over the crossbar to safety.
Forest were comfortable in the final stages of the contest and saw it out to take home a hard-earned three points from West London and put themselves right in the automatic promotion race.
Forest: Samba; Cash, Worrall, Figueiredo, Ribeiro; Watson (c), Sow; Lolley (Diakhaby 76'), Silva, Ameobi (Adomah 90'); Grabban (Yates 90')
Subs: Smith, Jenkinson, Semedo, Dawson
Goal: Lolley 14'
Booking: Samba 23'
Brentford: Raya; Dalsgaard, Jeanvier, Pinnock, Henry; Jensen (Marcondes 74'), Norgaard, Dasilva; Mbeumo, Watkins, Benrahma
Subs not used: Daniels, Yearwood, Valencia, Dervisoglu, Racic, Roerslev
Booking: Benrahma 39'
Referee: Tim Robinson
Attendance: 12,274 (1,642 away)