Introduction The heterogeneity in people with BPD and the range of specialised psychotherapies means that people with certain BPD characteristics might benefit more or less from different types of psychotherapy. Identifying moderating characteristics of individuals is a key to refine and tailor standard treatments so they match the specificities of the individual patient. The objective of this is to improve the quality of care and the individual outcomes. Thus, the aim of the current reviews is to investigate potential predictors and moderating patient characteristics on treatment outcomes for patients with BPD. Methods and analysis Our primary meta-analytic method will be the one-stage random-effects approach. To identify predictors, we will be using the one-stage model that accounts for interaction between covariates and treatment allocation. Heterogeneity in case-mix will be assessed using a membership model based on a multinomial logistic regression where study membership is the outcome. A random-effects meta-analysis is chosen to account for expected levels of heterogeneity. Ethics and dissemination The statistical analyses will be conducted on anonymised data that have already been approved by the respective ethical committees that originally assessed the included trials. The three IPD reviews will be published in high impact factor journals and their results will be presented at international conferences and national seminars. Protocol registration The IPD reviews, described in this study protocol, are registered with the PROSPERO International Prospective Register of Systematic Reviews (registration number: awaiting) Strengths and limitations of this protocolThese IPD-reviews are the first to systematically review and investigate psychotherapy for people with borderline personality disorder using individual participant data.The IPD-reviews will provide information on moderators and predictors in patients with borderline personality disorder that predict who may benefit most from which type of specialised psychotherapy.Individual participant data allows for a more precise risk of bias assessment and decreases the amount of unclear risk of bias in many of the included trials.A limitation to IPD-reviews in general is that data retrieval can be challenging.The IPD-reviews are limited to the outcomes and patient characteristics that have been assessed in the included trials.