IgA nephropathy (IgAN) is the most prevalent primary glomerular disease and has been recognized to carry a poor prognosis. It is therefore critical to identify the patients that will progress to ESKD and start treatments early. The current gold standard for diagnosis remains kidney biopsy. Histopathologic findings along with proteinuria, glomerular filtration rate, and hypertension remain the best-validated biomarkers for prognosis but do not provide enough granularity to guide treatment decisions. The current understanding of the pathophysiology of IgAN with the four-hit hypothesis has helped identify potential additional biomarkers that could become available in the foreseeable future. In this review we detail the existing data for the most promising biomarkers including galactose-deficient IgA1 and its corresponding autoantibody, markers of complement activation, as well as more nascent assays such as MicroRNAs, genomic, and microbiome biomarkers.