The prevalence of life-threatening, drug resistant microbial infections has challenged researchers to consider alternatives to currently available antibiotics. Teixobactin is a recently discovered “resistance proof” antimicrobial peptide that targets the bacterial cell wall precursor lipid II. In doing so, teixobactin exhibits potent antimicrobial activityagainst a wide range of Gram-positive organisms. Here we demonstrate that teixobactin and several structural analogues are capable of binding lipid II from both Gram-positive and Gram-negative bacteria. Furthermore, we show that when combined with known outer membrane-disrupting peptides, teixobactin is active against Gram-negative organisms.