Background <p>The identification of reliable biomarkers for clinical diagnosis and prognostic evaluation of severe pneumonia remains challenging. Long non-coding RNA (lncRNA) TINCR, along with its genetic variant rs2288947, has been suggested to play a role in the pathophysiology of severe pneumonia<b>.</b> This study aimed to examine the relationship between the rs2288947 polymorphism and the risk of developing severe pneumonia, the degree of inflammatory response, and 28-day outcomes in pediatric patients.</p> Methods <p>A total of 355 children diagnosed with severe pneumonia and 326 healthy controls were included. Plasma lncRNA TINCR expression was measured via qRT-PCR, and rs2288947 genotyping was performed using the TaqMan assay. 28-day survival based on Kaplan–Meier analysis were assessed. Multivariate Cox regression was employed to determine independent prognostic factors.</p> Results <p>Expression of lncRNA TINCR was significantly reduced in the severe pneumonia group compared to controls. At the rs2288947 locus, the presence of the A allele was correlated with downregulated expression of the lncRNA TINCR. Carriers of the GA or AA genotypes consistently demonstrated decreased lncRNA TINCR expression levels. The AA genotype and the A allele of rs2288947 were associated with an elevated risk of severe pneumonia. Patients carrying the GA + AA genotypes showed higher levels of inflammatory markers (WBC, CRP, PCT, neutrophils) and a lower 28-day survival rate. The rs2288947 polymorphism was identified as an independent prognostic factor.</p> Conclusions <p>The rs2288947 variant may represent a useful biomarker for evaluating susceptibility and predicting prognosis in pediatric severe pneumonia.</p>