The addition of either docetaxel or an androgen receptor signalling pathway inhibitor (ARSi) to androgen-deprivation therapy (ADT) has become the standard of care for metastatic castration-sensitive prostate cancer (mCSPC) patients. Recent phase III data support even greater survival impact of a triplet regimen with ADT plus docetaxel plus an ARSi (abiraterone or darolutamide) compared to ADT plus docetaxel. To evaluate whether the addition of an ARSi to ADT improves outcomes of mCSPC patients treated with docetaxel. We searched MEDLINE/PubMed, the Cochrane Library, and ASCO Meeting abstracts for randomised clinical trials (RCTs) testing the combination of ARSi + ADT in mCSPC men who received docetaxel. Data extraction was conducted according to the PRISMA statement. Summary hazard ratio (HR) was calculated using random- or fixed-effects models. The statistical analyses were performed with RevMan software (v.5.2.3). Five RCTs were selected. Triplet therapy improved overall survival (OS) compared to ADT + docetaxel in mCSPC patients (HR = 0.73; p < 0.00001). This intensified strategy maintained the OS benefit when the ARSi was administered concomitant to chemotherapy (HR = 0.72; p < 0.00001), but no statistical effect was detected if the ARSi was sequential to docetaxel (p = 0.44). Moreover, in the subgroup of men with de novo mCSPC, triplets significantly improved OS (HR = 0.72, p < 0.0001). The lack of access to raw data was the main limit of our analysis. Our results support a clear survival advantage of adding an ARSi to ADT in mCSPC patients treated with docetaxel, mainly when the ARSi was administered concomitantly to chemotherapy and in the subgroup of de novo mCSPC. •Triplet (ADT + docetaxel + ARSi) improves OS compared to ADT + docetaxel in mCSPC.•The OS advantage is greater with ADT + docetaxel + ARSi administered concomitantly.•In the subgroup of de novo mCSPC the triplet significantly improves OS.