The psychological impacts of injury have significant long-term implications on injury recovery. This review examined the effectiveness of interventions delivered within three months of injury on reducing the severity of posttraumatic stress disorder (PTSD), anxiety and depression symptoms. A systematic search of seven databases (PsycINFO, Medline, Web of Science, CINAHL, Embase, Scopus and Cochrane Library) identified 15,224 records. 212 full-text articles were retrieved, 26 studies were included in narrative synthesis, and 12 studies with lower risk of bias were included in meta-analyses. Prolonged exposure, and cognitive and behavioural interventions elicited improvements in PTSD, anxiety and depression symptoms; multidisciplinary interventions improved PTSD and depression symptoms; and education-based interventions had little impact on any psychological symptoms. Studies comprising risk stratified or stepped care methods showed markedly greater population impact through better reach, implementation and adoption. Meta-analyses revealed small-medium reductions in PTSD symptoms over the first 12 months postinjury (SMD = 0.32 to 0.49) with clinically meaningful effects in 64% of studies; reduced depression symptoms at 0–3 (small effect; SMD = 0.34) and 6–12 months postinjury (medium effect; SMD = 0.60), with clinically meaningful effects in 40% of studies; but no pooled effects on anxiety symptoms at any time. Altogether, exposure- and CBT-based psychological interventions had the greatest impact on PTSD and depression symptoms postinjury when delivered within three months of injury, with risk-stratified, stepped care having the greatest population impact potential.