The Morocco international's 11th league goal of the season in the third minute was enough to send Rene Girard's men five points clear of PSG at the summit
Younes Belhanda struck the game's only goal inside three minutes with a fine finish before Olivier Giroud missed a penalty in the second half against an enteprising, yet wasteful Toulouse side.
The visitors, who were hoping to build their lead with the knowledge that challengers PSG would face Lille on Sunday, immediately set about asserting their authority in the Pink City, and were rewarded inside three minutes.
Belhanda found space to deliver a fine shot past Ali Ahamada at his near post, for his 11th league goal of an already stellar campaign as la Paillade registered an early lead.
It could have been better for Rene Girard's men, who moments later saw Marco Estrada's free kick narrowly escape the bar, before a speculative Giroud header from an unassuming Belhanda cross almost deceived the goalkeeper.
For all of Toulouse's recent fluctuating form - they'd lost three out of their last four league games either side of a 3-0 thrashing of Lyon - le Tefece still posed a threat on the counter. A pin-point delivery from Moussa Sissoko saw Pantxi Sirieix evade his marker and launch an audacious low volley which narrowly flew into the side-netting.
Alain Casanova's men were markedly better in their attacking forays after that early set-back, and again almost equalised after a counter-attack leaving Montpellier uncertain at the back.
Adrien Regattin's over-hit cross found Pavle Ninkov whose initial effort was blocked by Geoffrey Jourden, before Franck Tabanou's rebound shot was hurriedly cleared off the line by Hilton as the sides entered the half with Montpellier leading 1-0.
In the second period, Toulouse would suffer yet another blow. A free-kick from the left by Estrada was perceived to be handballed by Tabanou, with the linesman signalling for a penalty amid vociferous dismay from the hosts.
Up stepped Giroud whose rather tame penalty was saved by Ahamada on the hour to deny what would've been a certain victory for the visitors.
Toulouse stepped up their effort after that boost, and were again denied by an efficient Jourden. A long ball found Emmanuel Riviere up front, and the former Saint-Etienne striker's fierce effort from an acute angle was ultimately unsuccessful.
The last 20 minutes or so were rather cagey, as the visitors switched to a defensive set-up to preserve their slender lead, and it worked as Toulouse were largely restricted with la Paillade well on their way to securing their 22nd league win of the season.
Following on from the result, Montpellier move five points clear of leaders PSG. Rene Girard's men encounter Evian on Tuesday whilst Toulouse play relegation strugglers Brest on Wednesday.