Ivan Langr, a spokesman for the Liberec Zoo, says the lions - 14-year-old Sultan and 11-year-old Elsa - managed unexpectedly to enter an open-air area occupied by the 17-year-old Tiger, named Isabella.
Langr said authorities were not able to prevent the killing, which took place Thursday morning.
The Liberec Zoo is the only one in the Czech Republic that has white tigers.
White tigers are the result of both parents having a recessive gene for white coloration. They are rare in the wild because standing out in the jungle hinders their efforts to catch prey.