The beloved animal was protecting Cecil's lion cubs after he was shot dead by Minnesota dentist Walter Palmer earlier this month, sparking outrage around the world.
Jericho is believed to have been gunned down during an illegal hunting operation in Hwange National Park on Saturday afternoon during.
Johnny Rodrigues, Chairman for Zimbabwe Conservation Task Force, said in a statement: 'It is with great sadness and regret that we report that Jericho was shot dead at 4pm this afternoon.
'We are absolutely heartbroken. We have no further details but will advise as soon as we know more.'
Before his death there had been concerns Jericho would not be able to hold the territory of Cecil's cubs alone and could be chased away by rival lions.
Unprotected, the lionesses and cubs are now under threat and also move away or be killed.
Last week Mr Rodrigues, told the Daily Mail Online Jericho was keeping the cubs safe from any rival males.
When contacted on Saturday a woman who answered the phone said he was too devastated to speak.