The term oligometastatic refers to an uncommon pattern of malignant dissemination to distant organs which can be safely treated with local approaches with the intent of improving overall survival. Although typically characterized by the number of metastases not surpassing 3 – 5 lesions, emerging evidence suggests that a diagnosis based on a single snapshot imaging does not sufficiently provide for an accurate detection of a true oligometastatic disease. In fact, in order to be amenable to successful local treatment, even aiming for cure, the following criteria have to be met. First, the disease progression has to be very slow, including tumour growth rate and formation of new metastases (probably less than 0.6 new metastases per year as shown in lung cancer). Moreover, implying the presence of only few lesions in limited organ sites, the overall tumour burden has to be low to enable safe ablation using local interventions. Last but not the least, there should be no occult metastases. Obviously, not all of these criteria can be checked easily, but the probability of an oligometastatic presentation increases when dealing with a metachronous (versus synchronous) manifestation with a long disease-free interval after primary treatment, and a series of follow-up imaging studies shows corresponding tumour growth kinetics. In addition, using complementary nuclear medicine and radiological imaging techniques and evaluating relevant laboratory parameters, such as circulating markers in some cancers, help us lower the detection threshold for subclinical disease. However, it has become clear that further improvement can only be accomplished by implementing biological classifiers. In this respect, promising data have recently been reported in relation to genetic determinants (e.g., SMAD4 loss in pancreatic cancer, PBRM1 mutation in renal cancer), epigenetic modifiers (e.g., 14q23-encoded microRNAs), and tumour-host interactions (immune response). In head and neck cancer, the most prognostically favourable group comprises patients presenting with an oligorecurrence of human papillomavirus (HPV)-positive oropharyngeal cancer in the lungs. Of note, oligorecurrence represents a state of metachronous dissemination in which oligometastases develop in patients with a controlled local or locoregional disease who are at least 3 – 6 months after the primary diagnosis. Therefore, post-treatment follow-up has a decisive role, and although current guidelines do not recommend routine radiological examinations in all head and neck cancer survivors, they can be justified in those potentially presenting with curable oligometastases. Besides that, in patients receiving systemic therapy for polymetastatic cancer, there are further clinical scenarios sharing some of the hallmarks of oligometastases. They include oligoprogression if few distant lesions evade disease control and start growing and oligopersistence if a complete response is achieved except for few persisting lesions which are either stable or partially decrease in size. Importantly, the same local techniques, typically surgical resection, stereotactic body radiotherapy, or radiofrequency ablation, can be employed in these settings, albeit not with a curative intent but rather to prolong survival or delay a change or reinitiation of systemic treatment. Taken together, despite providing intriguing options to improve patient care, the concept of oligometastatic disease is still far from being fully understood and furnishes thus ample research opportunities in the areas of disease biology, workup, and treatment. Gaining a better insight into the biological basis of an oligometastatic phenotype together with finetuning its clinical determinants will be indispensable for developing reliable composite prognostic models and proper patient selection. This will probably not be possible without simultaneous advances in imaging modalities, such as using molecular imaging with novel positron emission tomography (PET) tracers, or introducing liquid biopsy to clinical practice as part of residual disease monitoring and early recurrence detection. Finally, investigational treatment strategies seek to address various issues encompassing development of new drugs (e.g., epigenetic modifiers reversing polymetastatic to oligometastatic phenotype), technologies (e.g., improvements in external and internal radiotherapy), combinations of local and systemic therapies (especially with immune checkpoint inhibitors), treatment sequencing, innovative approaches to clinical trial design (e.g., adjusted endpoints, patient-reported outcomes), and other. Importantly, some of these new concepts hold the promise of becoming site-agnostic tools, thus of interest also to the head and neck cancer field, while other are more specific such as circulating Epstein-Barr virus (EBV) DNA monitoring in metastatic nasopharyngeal cancer or still experimental measurements of cell-free plasma HPV DNA in oropharyngeal cancer.