High-risk neuroblastoma (NB) often involves amplification of the neural MYC (MYCN) oncogene as well as mutations in ALK. Currently, high-risk NB presents significant clinical challenges, and additional therapeutic options are needed. Oncogenes such as MYCN and ALK result in increased replication stress in cancer cells, offering one such therapeutically exploitable option. Here, we followed up on earlier phosphoproteomic analyses that identified ATR activity in ALK-driven NB cell lines. We tested several ATR inhibitors, identifying BAY 1895344 as the most potent inhibitor of NB cell growth and proliferation. Using RNA-Seq, proteomics and phosphoproteomics we characterized the response of NB cells and tumours to ATR inhibition, identifying key components of the DNA damage response (DDR) as well as ATRX, MYCN, E2F and DCK among other ATR targets in NB cells. ATR inhibition with BAY 1895344 also produced robust responses in mouse NB models. Remarkably, a 2 week protocol combining ATR and ALK inhibition led to complete regression of NB tumours in two independent NB genetically modified mouse tumour models. These results suggest that NB patients, particularly in high-risk groups with oncogene induced replication stress, may benefit from inhibition of ATR as therapeutic intervention.