In this study, we isolated a mycobacteriophage infecting Mycobacterium smegmatis mc2155 from a soil sample collected in Shandong Province in China. This phage was named Shandong1. It is a member of the family Siphoviridae with an isometric head and a long tail. Its genome was found to be 60,618 bp long with 67.46% G + C content and 96 putative protein-coding genes. No tRNA-encoding genes were identified. Comparative genomics analysis showed that the mycobacteriophage Shandong1 should be considered a member of a new species in mycobacteriophage cluster K.