Antilipopolysaccharide factors (ALF) are antimicrobial peptides in the humoral defense mechanism in shrimps, with broad activity against bacteria, viruses, and fungi. Several ALF and their isoforms have been reported in decapod crustaceans, showing structural and functional differences. This work describes the Litopenaeus vannamei antilipopolysaccharide factor 5, initially found in a hepatopancreatic transcriptomic database. The LvALF5 gDNA sequence is 1,619 bp, with a complete mRNA sequence of 934 bp. The ORF encodes a 124 amino acids sequence, including a 26 amino acids signal peptide and 98 amino acids mature peptide, highly similar to the Litopenaeus stylirostris ALF peptide sequence (96%). This peptide shows main differences in the LPS-binding domain, having only 2 positive amino acids conserved. The evolutionary analysis shows that LvALF5 is in cluster 2, which indicates that structurally it has characteristics of the other white shrimp isoforms. LvALF5 is highly expressed in healthy shrimp hemocytes, 20-fold more than in other tissues. It is up-regulated during bacterial and viral challenges. Inhibition experiments using a recombinant LvALF5 show a more efficient antibacterial activity against Vibrio parahaemolyticus than Staphylococcus aureus bacteria strains.