Diabetes mellitus is associated with significant morbidity and premature mortality for which heart failure (HF) is a major cause. HF may be due to ischaemia, hypertension, uraemia, or a specific diabetic cardiomyopathy, and multiple causes may co-exist. A recent systematic review suggests that >40 % of people with type 2 diabetes have diastolic dysfunction without a reduction of cardiac systolic function. In people with type 1 diabetes without known cardiovascular disease, 16 % had systolic or diastolic dysfunction. Early diabetic cardiomyopathy is asymptomatic and can progress to symptomatic HF via increasing cardiomyocyte hypertrophy and death as well as cardiac fibrosis. The 5-year mortality rate for HF is similar or worse than many common cancers. There have been significant recent advances in HF treatment including sodium-glucose co-transport 2 inhibitors (SGLT2i) and angiotensin receptor-neprilysin inhibitors (ARNi), and promising therapies such as finerenone and glucagon-like peptide-1 receptor agonists (GLP-1RA). SGLT2i, finerenone, and GLP-1RA may also have a role in HF prevention in asymptomatic diabetic cardiomyopathy. While there is currently no specific treatment for diabetic cardiomyopathy that goes beyond general HF treatment, there is promising research into innovative technologies such as gene and stem cell therapies. Also, digital technologies will likely have an increasing role in diabetic cardiomyopathy treatment. Herein we review the pathophysiology, diagnosis, and treatment of diabetic cardiomyopathy, with a focus on existing, emerging, and potentially promising novel therapies. We provide practical tables that summarise treatments at each stage as well as important practice points for commonly prescribed drugs.