Termites are amongst the most abundant terrestrial animals on earth, largely due to their ability to digest lignocellulose, the most abundant organic molecule on earth. Lignocellulose is broken down in the termite gut with the help of symbiotic bacteria. Studies using the 16S rRNA marker have shown that termites and their gut bacteria have had a complex evolutionary history. Although many gut microbes are found nowhere else than in termite guts, bacterial communities do vary with termite diet. To understand how gut bacterial lignocellulose digestion evolved across 150 million years of termite evolution, we sequenced gut meta-genomes of 146 termites, selected to represent host diversity across the termite tree of life. We found that even though the breakdown of dietary wood can be performed by multiple bacterial taxa, they are governed differently by ecological and evolutionary pressures. These results suggest lignocellulose digestion by gut bacteria are functionally redundant across the termite tree of life.