Lethal is something that is capable of causing death to a living being. For example, a Lethal injection.It may also refer to:A Lethal gene, a gene which produces an organism which dies before reproducingLeigh Matthews, Australian rules footballer frequently referred to as "Lethal" or "Lethal Leigh"Lethal , a 2005 B-movie starring Heather Marie Marsden and Lorenzo LamasLethal is an Australian record company