Abstract Objectives Growth failure can result from various underlying causes, necessitating a thorough evaluation. Reninoma, a rare renin-secreting tumor, is an uncommon cause of hypertension, especially in paediatric patients, and has not been associated with growth failure until now. Case presentation An 11-year-old girl presented with complaints of poor height gain, headaches, increased thirst, and vomiting. The evaluation revealed severe hypertension and hypokalemic alkalosis. Investigations indicated renin-dependent hypertension, and imaging identified a right renal mass. Renal venous sampling confirmed renin production from the tumor. A right open partial nephrectomy was performed, resulting in the normalization of blood pressure and improved growth. Over the following years, she achieved a significant catch-up growth, regaining her original height percentile and the target adult height. Conclusions This case adds to the limited literature on paediatric reninoma. It highlights a rare presentation of reninoma causing hypertension and growth failure in a child. The growth failure was likely due to hypokalemic alkalosis-induced low insulin-like growth factor 1 (IGF-1) levels, a mechanism not previously documented in paediatric reninoma cases. Surgical excision of the tumor led to normalization of blood pressure and metabolic alkalosis with significant growth recovery.