Periodontitis is one of the leading causes of tooth loss in the adult population. This disease can be classified into various categories, and one of the most destructive amongst them is aggressive periodontitis (AgP). The incidence of AgP is lower than other types of periodontitis. However, it affects young individuals and can cause severe destruction of tooth-supporting structures including tooth loss if left untreated. The current classification for diagnosing periodontal disease was established by the American Academy of Periodontology (AAP) in 1999. This classification provided strict guidelines to aid in AgP diagnosis. These include three main factors: systemically healthy individual, rapid loss of clinical attachment, and familial aggregation. In spite of these specific guidelines, AgP diagnosis is often missed clinically due to various reasons. There is still a vast variation in the diagnostic criteria for identifying AgP and not all practitioners utilize the AAP guidelines for their diagnosis. Furthermore, the definition of the disease might be changing in the future to better represent the current understanding of the disease. Since early diagnosis and prompt treatment is key in treating these patients, it is important to have calibration in the diagnosis process. This review aims to identify sources of variation and ambiguity in diagnosing AgP among dental practitioners. For this purpose, we have conducted an extensive literature search and outlined the various diagnostic aids for AgP patients reported in the literature. Understanding and correcting these variations can simplify the diagnostic process leading to faster treatment of patients affected with AgP. This review also emphasizes the importance of minimizing the bias in identifying patients with AgP and highlights the best tools for this purpose.