Here, we report a new member of rV5-like phages, Escherichia phage vB_EcoM-Pr121LW, isolated from soil samples and lytic against different serogroups of Shiga toxin-producing Escherichia coli (STEC) strains. With molecular properties that contain no antibiotic resistance, virulence, or lysogenic genes, this phage is a potential biocontrol agent against STEC.