The charity is collaborating with the National Farmers Union (NFU) to urge people not to release the lanterns which can cause damage as they fall back to earth.
But both organisations said it is not just sky lanterns which pose a threat at this time of year with a increase in the number of fireworks being let off during the festive season.
Alan Hiscox, Director of Safety at The BHS said: “Sky lanterns and fireworks may be enjoyable for some people, but they can cause considerable trauma or distress to horses.
“We would urge anyone planning on setting them off during the festive period to consider the effect it may have on local animals and the potential fire risk to stables or outbuildings.
“While the decorative lanterns may look pretty floating across the night’s sky, they can cause horrific injuries to animals, or even death, when they come back down to Earth.”
The charity said it has received more than 20 reports from horse owners who have had incidents involving sky lanterns. Three of these reports were horse fatalities and six involved horse injuries.
“As prey animals, horses can be frightened by sky lanterns looming above them,” a spokesman for the charity said.
“With no way of controlling where they travel or where they land, sky lanterns also pose a fire risk to buildings, stables and barns. The environmental harm of these lanterns can also be devastating to the UK’s green spaces. The BHS encourages horse owners and farmers to be vigilant in checking their fields and hedgerows.”
The NFU said around 200,000 sky lanterns are sold and released each year. There is no national UK legislation regulating sky lanterns.