Objective: Few studies have examined ovarian borderline tumor (BOT) risk associated with analgesics, and with inconclusive findings. The aim was to examine serous borderline tumor (SBT) or mucinous borderline tumor (MBT) risk associated with use of paracetamol, low-dose aspirin, or non-aspirin non-steroidal anti-inflammatory drugs (NSAIDs). Methods: We identified all women with SBTs or MBTs in the Danish Pathology Data Bank, 1997–2015. Using risk-set sampling, we randomly selected 15 controls per case. We excluded women with previous cancer (except non-melanoma skin cancer) and controls with bilateral oophorectomy/salpingo-oophorectomy. Information on redeemed prescriptions of medications/confounders was identified from nationwide registries. We used conditional logistic regression to estimate adjusted odds ratios (ORs) and 95% confidence intervals (CIs). Results: We observed a decreased MBT risk among recent paracetamol users (OR = 0.77; 95% CI: 0.60–0.98), but no association with SBTs. Regarding non-aspirin NSAIDs, we found an increased SBT risk with recent (OR = 1.29; 95% CI: 1.11–1.51) and former use (OR = 1.19; 95% CI: 1.04–1.37), and an elevated MBT risk with recent use (OR = 1.14; 95% CI: 0.97–1.33). Low-dose aspirin use did not seem related with SBT risk, and the association with MBTs was unclear. Conclusions: No strong associations between the examined medications and BOTs were observed. However, our nationwide case-control study may suggest that recent paracetamol use could have a chemopreventive effect on MBTs, whereas neither low-dose aspirin nor non-aspirin NSAIDs use seem to protect against SBTs or MBTs. Larger studies are needed to firmly establish a potential association between these medications and BOT risk.