PurposeThis study aims to compare the expectations of non-collaborating professionals and the actual opinions of collaborating professionals regarding success factors of horizontal logistics collaboration (HLC) and investigates the reasons behind the observed differences.Design/methodology/approachThis study employs a mixed-method approach. First, a survey is conducted to collect data from two samples representing collaborating and non-collaborating industry professionals. Second, confirmatory factor analysis (CFA) is used to compare the measurement models from the two samples and identify their similarities and differences. Third, a Delphi study is conducted to identify factors limiting collaborative behavior.FindingsThe results show that collaborating professionals exhibit lower levels of joint relationship efforts and trust than expected. This is primarily due to inadequate information sharing, poor collaboration formalization and the absence of a clear costs and benefits allocation mechanism.Practical implicationsThe findings indicate that, in HLC, managers should give high importance to facilitating timely and complete information exchange, putting in place an acceptable costs/benefits allocation mechanism, formalizing the collaboration and prioritizing integrity over competency when selecting partners.Originality/valueTo the best of the authors’ knowledge, this is the first study that shows the existence of differences between industry professionals' pre-collaboration expectations and the actual experiences in HLC. This is also the first study that points to the exact HLC enablers that fail in practice and the barriers responsible for it.