Amyotrophic lateral sclerosis (ALS) is a progressive, degenerative neuromuscular disease with limited treatment options. The diagnosis of ALS can be challenging for numerous reasons, resulting in delays that may compromise optimal management and enrollment into clinical trials. Several studies have examined the process and challenges regarding the clinical diagnosis of ALS. Twenty-one studies that were almost exclusively from the English literature published between 1990 and 2020 were identified via PubMed using relevant search terms and included patient populations from the United States, Canada, Japan, Egypt, and several countries in South America and Europe. Probable or definitive ALS patients were identified using El Escorial or revised El Escorial/Airlie House Criteria. Time to diagnosis or diagnostic delay was defined as mean or median time from patient-reported first symptom onset to formal diagnosis by a physician, as recorded in medical records. The typical time to diagnosis was 10-16 months from symptom onset. Several points of delay in the diagnosis course were identified, including specialist referrals and misdiagnoses, often resulting in unnecessary procedures and surgeries. Bulbar onset was noted to significantly reduce time to ALS diagnosis. Future interventions and potential research opportunities were reviewed.