Childhood obesity is a significant and growing issue, with the WHO recognising worldwide childhood obesity rates as an epidemic. Primary care is often the first point for monitoring a child's development over time, hence could play an integral part in recognising and addressing childhood obesity. As a result, our systematic review has two objectives. The primary objective is to review the current evidence on best practices in diagnosing and treating childhood obesity. The secondary objective is to review recent qualitative studies looking into the view of primary care practitioners on the treatment and diagnosis of childhood obesity. The rationale for this is to help determine what opportunities there are in primary care in the NHS to tackle childhood obesity. Using searches in MEDLINE, EMBASE, PSYCHINFO, HMIC and NHS evidence over a five-year period from March 2014 to March 2019, a total of 37 studies were eligible for inclusion in the review. Out of these, 25 studies identified exploring the diagnosis and treatment of childhood obesity. A few key themes in these studies were identified, including motivational interviewing, m-health, tools and resources used in consultations, the use of dieticians in the primary care team and factors concerned with the identification of obesity in children. The rest of the 12 qualitative studies involved eliciting the views of direct stakeholders about the diagnosis and treatment of obesity in children. Eight of the studies investigated providers' views towards the role of primary care practitioners in treating childhood obesity, two investigated the parents of obese children's perspectives and the other two investigated general practitioners' (GPs) views towards specific tools and resources. Regarding our primary objective, our findings showed many studies looking at interventions to reduce the BMI in obese children fail to do so in a statistically significant way. However, a few interventions have been more consistent in reducing BMI and obesogenic behaviours. Those interventions include ones utilising the motivational interviewing technique and those targeting families, rather than children. Another key finding was that tools and resources available to primary care providers can significantly impact their ability to diagnose and treat obesity, particularly when looking at the detection. Finally, evidence regarding the clinical effectiveness of e-health is limited, with views on their use also mixed. Regarding our secondary objective, the qualitative research identified demonstrated many common views from GPs across different countries. It showed healthcare providers (HCPs) perceiving the parents as lacking in motivation to address the issue, HCPs not wanting to damage the relationship with their patients due to it being a sensitive topic to bring up, and a lack of time, training and confidence. However, some of these views may not be generalisable to the UK due to cultural and system differences.