The company, based at Platts Common Industrial Estate in Hoyland, designs, builds, services and inspects road tankers for carrying petroleum and LPG gas.
Over the past 20 years the company has secured nearly 75% of the domestic market, with customers including Shell, Certas, Calor Gas, Morrisons, Sainsburys and Asda.
Increasing demand has seen the company double turnover to £15m and expand its workforce seven-fold to 150 employees.
Now, RTN is embarking on a further period of expansion and aims to create around 15 new jobs within the next year in areas such as design, fabrication, welding, electronics, inspection and administration.
The engineering company’s growth plans are being supported by Enterprising Barnsley, the economic development arm of Barnsley Council.
RTN operations director Don McKelvie said: "We have grown year-on-year since we moved to Barnsley in 1993 and are very proud to be creating more skilled, high-value jobs in manufacturing right now.
"A lot of people just don’t realise that Barnsley is the centre of the UK road tanker manufacturing industry – and it’s not happened here by accident, our growth has been down to sustained investment in plant, premises, workforce and innovation."
Enterprising Barnsley is currently supporting RTN with its recruitment and training drive and has in the past helped the company secure a Leeds City Region grant to help fund a previous expansion.
Enterprising Barnsley business development manager Steve Hawkins said: "Road Tankers Northern is a major local success story and continues to grow and create new, skilled engineering jobs in our borough.
"Their strength is their ambition and attitude, combining tried and tested engineering techniques with a constant desire to innovate and improve their product to offer customers more. We’re delighted to help them recruit still more employees and apprentices."