Among those acquitted of a charge of involuntary manslaughter by the Qatar Court of Appeal, was Sheikh Ali Bin Jassim al-Thani, Qatar's ambassador to Belgium.
A Qatari government website also says Thani is the country's "head of mission to the European Union".
Thani was co-owner of the "Gympanzee" nursery at a well-known Doha shopping mall, the Villagio, where the fire occurred in May 2012.
Many of the children suffocated after a blaze broke out at a nearby Nike sports store, caused by faulty wiring.
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Thani was among four people appealing a 2013 involuntary manslaughter conviction imposed by a criminal court in Qatar.
That conviction left the four facing a maximum of six years in prison, reported Doha News, an English-language news website.
But in a five-hour long ruling on Monday the convictions against the individuals were thrown out.
The judge did find the mall's owners guilty of involuntary manslaughter, which means family victims of the tragedy could receive "blood money" as compensation.