Idiopathic overactive bladder syndrome (iOAB) is a prevalent condition in urological practice. The variability in management between specialists and between centers remains high. Even existing guidelines contain inconsistencies. We aimed to develop a treatment algorithm for iOAB for use in daily clinical practice. From October 2018 till November 2019, a Delphi study was conducted to obtain expert consensus on the management of iOAB. Members from the Belgian Working Group of Functional Urology were asked to rate online statements, based on gaps and variabilities between the American Urology Association (AUA), European Association of Urology (EAU) and International Consultation on Incontinence (ICI) guidelines on iOAB. The consensus was reached if ≥75% of the panel agreed on the level of appropriateness. Two Delphi rounds and an open discussion session were held. Twenty out of 49 members completed the first round and 18 completed the second round. The consensus was reached on 44/143 statements and 15/56 statements in the first and second round, respectively. The consensus was reached on criteria by which to phenotype OAB patients, the terminology relating to the first-, second- and third-line treatment, the duration of therapies, the chronological order, and the choice between therapies. No consensus was reached on the role of percutaneous tibial nerve stimulation (PTNS) in the treatment algorithm. A flowchart reflecting the current attitude and approach of a Delphi expert panel towards the treatment of iOAB was developed. We propose its use in daily clinical practice to increase the standardization of OAB treatment.