The natural gas engine technology firm said the loss amounted to 53 cents per share for the quarter ended Sept. 30, compared with a loss of $32.5 million or 59 cents per share a year ago.
Revenue totalled $46.5 million, up from $30.7 million.
The results were boosted by the acquisition earlier this year of BAF Technologies Inc. and its subsidiary, ServoTech Engineering, Inc., from Clean Energy Fuels Corp. and increased sales of its high pressure direct injection systems.
Westport chief executive David Demers called 2013 a transition year for the company as it shifts from working to create markets to full commercial operation and profitability.
"I think we have the right product at the right time to see a real breakthrough that will establish natural gas as a major fuel for trucks around the world which will be a catalyst for further investment in refueling infrastructure," Demers said.
In its outlook, the company said it expected revenue for the full year to total between $160 million and $180 million.
Westport develops engines that use fuels such as compressed natural gas, liquefied natural gas, hydrogen and renewable natural gas fuels such as landfill gas.