Diabetes mellitus is a chronic condition in which the body does not produce enough or does not respond normally to insulin, a peptide hormone produced by the pancreas that promotes the absorption of glucose from the blood into cells. There are 3 main types of diabetes: type 1 diabetes, type 2 diabetes, and gestational diabetes. Type 1 diabetes is an autoimmune condition in which the insulin-making beta cells of the pancreas are destroyed. Often diagnosed in children and young people, common symptoms include frequent urination, increased thirst and hunger, weight loss, blurry vision, tiredness, slow wound healing, and diabetic ketoacidosis. Type 2 diabetes, which accounts for approximately 90% of diabetes cases in Canada, is a complex metabolic disorder where the pancreas is still capable of producing insulin but not in sufficient quantities to meet the body’s needs, often a result of insulin resistance. A number of genetic, environmental, and behavioural factors can increase the risk for developing type 2 diabetes, such as age, body weight, diet, use of tobacco or alcohol, and levels of physical activity. Gestational diabetes is a condition characterized by hyperglycemia that some people may experience during pregnancy. While it typically resolves itself after birth, people who experience gestational diabetes may be at increased risk of developing type 2 diabetes later in life. Diabetes Canada estimates that 1 in 10 Canadians are diagnosed with type 1 or type 2 diabetes, and that diabetes has direct costs to the health care system of approximately $3.8 billion per year. The incidence and costs associated with diabetes are expected to increase by 2030. While not the case for all people with diabetes, many individuals with diabetes may require insulin therapy to improve their body’s ability to metabolize glucose. Insulin therapy is typically delivered using multiple daily insulin injections (MDII; via vials and syringes or insulin pens), insulin pumps, or using novel approaches such as sensor-augmented pumps or hybrid closed-loop insulin delivery systems. People with diabetes must check their glucose levels regularly to inform the appropriate doses of insulin to be delivered. Traditionally, blood glucose levels are tested using a blood glucose metre. As part of this process, the individual uses a lancet loaded onto a finger-prick device to puncture their skin and to cause bleeding. A drop of blood is then collected on a test strip and analyzed by the glucose metre. This process is referred to as self-monitoring blood glucose (SMBG). Alternatively, people with diabetes may use flash glucose monitoring (FGM) or continuous glucose monitoring (CGM) devices to inform their insulin dosing decisions. FGM devices, such as the FreeStyle Libre, and CGM devices use an externally-worn glucose sensor with a small filament inserted under the skin, typically on a person’s upper arm, to measure interstitial levels of glucose. In the case of FGM devices, the sensor is scanned with a separate reader that transmits and stores glucose readings for the previous 8 hours. FGM systems may provide more than just a glucose reading, such as arrows indicating glucose trends and alarms in cases where hypoglycemia, hyperglycemia, or signal loss are detected. In December 2019, Ontario Health (Quality) recommended public funding of FGM systems for people with type 1 diabetes who experience recurrent hypoglycemia despite frequent self-monitoring of blood glucose and efforts to optimize insulin management and for people with type 2 diabetes requiring intensive insulin therapy (MDII or continuous subcutaneous insulin infusion) who experience recurrent hypoglycemia despite frequent SMBG and efforts to optimize insulin management. This recommendation, which was based on the guidance of the Ontario Health Technology Advisory Committee, was informed by a health technology assessment completed by Ontario Health (Quality), in collaboration with CADTH, that assessed clinical evidence, economic evidence, and patient values and preferences. In short, the findings of the clinical review conducted as part of the health technology assessment suggested that moderate-quality evidence demonstrated that FGM improved diabetes management among adults with well-controlled types 1 diabetes and adults with type 2 diabetes requiring intense insulin therapy. Of the 6 studies included in the clinical review, only 1 recruited participants younger than 18 years of age. The objective of the current report is to review the literature regarding the clinical effectiveness of FGM versus SMBG, in pediatric populations with diabetes requiring insulin therapy, published since the health technology assessment. Additionally, this report aims to summarize clinical evidence that has assessed the effectiveness of alarms available on modernized FGM systems (i.e., FreeStyle Libre 2) in people of all ages with diabetes requiring insulin therapy.