Toyota sold 5.02 million vehicles worldwide between January and June, which is less than the earlier figures from Volkswagen of 5.04 million units shifted in the same period.
US-based General Motors was at third place with 4.86 million in sales.
Toyota snapped decades-long reign of the GM as the world's top automaker in 2008 but the company failed to keep the crown in 2011 as earthquake-tsunami disaster adverselt impacted production and disrupted the supply chains of the country's automakers.
But Toyota rebounded in 2012 and overtook its Detroit rival, which sells the Chevrolet and luxury Cadillac brands, to end on top.
Toyota, however, has estimated that its sale may slip to 10.15 million from a record 10.23 million vehicles in 2014, largely due to a shaky outlook for Japan. The company is currently focusing on beefing s up its focus on quality after a string of safety scandals.
Toyota announced in April that it was ending a freeze on building new factories by unveiling plans for a $1.0 billion plant in Mexico and another production line in China.
In 2013, the carmaker began operating a new plant in Thailand but the company had since then halted investment as the global car market struggled with oversupply and weak demand.