The purpose of this paper is to review the features and behaviour of the odontogenic keratocyst (OKC), now officially known as the keratocystic odontogenic tumour (KCOT); to analyze a series of histologically confirmed KCOT cases; and to review and discuss the redesignation of KCOT and the implications for treatment. Based on a literature review, more aggressive treatment — either resection or enucleation supplemented with Carnoy’s solution with or without peripheral ostectomy — results in a lower recurrence rate than enucleation alone or marsupialization. However, the recurrence rate after marsupializa- tion followed by enucleation is not significantly higher than that after aggressive modal- ities. In a case series of 21 patients (27 KCOTs), recurrence rate was 29%, consistent with published data; all recurrences occurred within 2 years after intervention. The size of most lesions was 0–15 cm2 (average 14 cm2) measured radiographically. WHO’s reclassification of this lesion from cyst to tumour underscores its aggressive nature and should motivate clinicians to manage the disease in a correspondingly aggressive manner. The most effective treatments are enucleation supplemented with Carnoy’s solution, or marsupial- ization with later cystectomy. Future treatment may involve molecular-based modalities, which may reduce or eliminate the need for aggressive surgical management.