Background: Communication partner training (CPT) is an umbrella term for a complex behavioural intervention for communications partners (CPs) of people with aphasia (PWA) and possibly PWA themselves, with many interacting components, deployed in flexible ways. Recent systematic reviews (Simmons-Mackie, Raymer, Armstrong, Holland, & Cherney, 2010; Simmons-Mackie, Raymer, & Cherney, 2016) have highlighted the effectiveness of CPT in addressing the skills of conversation partners and the communicative participation of people with aphasia but have suggested that CPT has been variably delivered, with no clear picture of what the essential elements of CPT are and how CPT is expected to achieve its results through hypothesised mechanisms of change (Coster, 2013). Aim: This paper aims broadly to consider specification of CPT and describes how CPT has been conducted overall and in relation to treatment recipients. Recommendations for CPT and areas for future research are considered. Methods & Procedures: A critical review and narrative synthesis was carried out through: (i) the systematic application of the 12-item TIDieR checklist (Hoffmann et al., 2014) to the 56 studies appraised in the Simmons-Mackie et al. (2010, 2016)) reviews, providing a quantitative overview of the completeness of CPT intervention reporting; and (ii) a qualitative synthesis of the reviewed CPT literature according to TIDieR items. Outcomes & Results: Half of the TIDieR checklist items were reported by 71% or more of the studies, and the rest of the items were reported by 0–63% of studies. TIDieR items relating to the treatment (goal, rationale or theory of essential elements, materials and procedures) and provision (provider, mode, timing, dose) were more frequently reported; however, the level of detail provided was often inadequate or incomplete. The interventions were insufficiently specified to enable replication for most of the studies considered. The most infrequently reported items were: name, location, intervention tailoring and modification, and planned and actual intervention adherence/fidelity. Conclusion: For a better understanding of an intervention, it is necessary to identify and describe potentially central elements and perhaps especially in complex interventions as CPT, where it is likely also more difficult. Whilst the reviewed CPT studies are on average reporting on slightly more than half of the TIDieR items, they are overall insufficiently detailed. Some items appear easier to report on, whereas other items have not been attended to, are too complex in nature to give a full report on, or simply have not been relevant for the individual study to include.