The objective of this study was to describe factors affecting pain after pediatric tonsil surgery, using patient reported pain-related outcome measures (pain-PROMs) from the National Tonsil Surgery Register in Sweden. In total, 32,225 tonsil surgeries on children (1 to <18 years) during 2009–2016 were included; 13,904 tonsillectomies with or without adenoidectomy (TE ± A), and 18,321 tonsillotomies with or without adenoidectomy (TT ± A). Adjustments were made for variables included in the register to compensate for contributable factors in the analysis. When compared to TE ± A for surgical indication obstruction, TT ± A resulted in lower pain-PROMs, shorter use of postoperative analgesics, earlier return to regular food intake, and lower risk for contact with health care services due to pain. Children who underwent TE ± A because of obstruction problems stopped taking painkillers and returned to normal eating habits sooner, compared to children who underwent TE ± A for infectious indications. In both indication groups, TE ± A performed with hot rather than cold technique (dissection and haemostasis) generally resulted in higher pain-PROMs. Older children reported more days on analgesics and a later return to regular food intake after TE ± A than younger ones. No clinically relevant difference between sexes was found. Between 2012 and 2016 (pre-and post-implementation of Swedish national guidelines for pain treatment), the mean duration of postoperative analgesic use had increased. In conclusion, TE ± A caused considerably higher ratings of pain-related outcome measures, compared to TT ± A. For TE ± A, cold surgical techniques (dissection and haemostasis) were superior to hot techniques in terms of pain-PROMs. Older children reported higher pain-PROMs after TE ± A than younger ones.