Low back pain (LBP) is a common presentation to the ED, and a frequent cause of disability globally. The ED management is often associated with high rates of imaging, misuse and overuse of pharmacology and subsequent financial implications. Given this, improved quality of care for patients with LBP in ED is essential. This rapid review investigated best practice for the assessment and management of LBP in the ED. PubMed, CINAHL, EMBASE, TRIP and the grey literature, including relevant organisational websites, were searched in 2015. Primary studies, systematic reviews and guidelines were considered for inclusion. English-language articles published in the past 10 years that addressed acute LBP assessment, management or prognosis in the ED or acute setting were included. Data extraction of included articles was conducted, followed by quality appraisal to rate the level of evidence where possible. The search revealed 1538 articles, of which 38 were included in the review (n = 8 primary articles, n = 13 systematic reviews and n = 17 guidelines). This rapid review provides clinicians managing LBP in the ED a summary of the best available evidence to risk stratify and enhance the quality of care, optimising patient outcomes. Consistent evidence was found to support the use of 'red flags' to screen for serious pathologies, diagnostic tests being reserved for use only in the presence of red flags, the judicious prescribing of opioids, identification of psychosocial risk factors as predictors of poorer outcome and promotion of early return to work and function.