Inflammatory bowel disease (IBD), historically subdivided into Crohn’s disease and ulcerative colitis, is a very heterogeneous condition. While the tendency in medicine is to try and reduce complexity, IBD is a disease that cannot justify a one-size-fits-all principle. Our current clinical classification tools are suboptimal and need further refinement, to capture at least in part the variety of phenotypes encountered in daily clinical practice. Although these revised classification tools alone will not be sufficient and should be complemented by more detailed molecular subclassifications, optimised clinical phenotypes can contribute to improved trial designs, future translational research approaches and better treatment outcomes.