Background: Extensive variation in the terminology used for paediatric diagnoses across the speech and language therapy research literature is an internationally recognized problem. Little is known, however, about how and how often diagnoses are given in a clinical context. In the UK, speech and language therapists (SLTs) identify and support children who have speech and language needs. To understand and address clinically rooted terminological issues that may directly impact clients and families, there is a need for exploration of how the diagnostic process is operationalized in practice. Aim: To identify, from the perspective of SLTs, areas that present as enabling and obstructive factors to conducting diagnosis in clinical practice. Methods & Procedures: Taking a phenomenological approach, 22 paediatric SLTs were interviewed using a semi-structured format. Thematic analysis revealed a number of factors that were either classified as 'enabling' or 'obstructive' to their diagnostic processes. Outcomes & Results: Participants were often hesitant to provide a diagnosis to families and universally reported the need for targeted guidance, which accounts for the demands of current clinical practice, to guide their diagnostic process. Four enabling factors were identified from participant data: (1) working to a medical model, (2) the availability of collegiate support, (3) recognizing the benefits of diagnosis,, and (4) relating to the needs of the family. Seven themes portrayed obstructive factors in practice: (1) the complex presentation of clients, (2) the risk of giving a 'wrong' diagnosis, (3) participants' uncertainty about diagnostic criteria, (4) insufficient training, (5) service models, (6) concerns about stigma and (7) not having enough clinical time. The obstructive factors created dilemmas for participants and resulted in hesitancy to give a diagnosis, potentially contributing to delays in diagnosis experienced by families as reported in previous literature. Conclusions & Implications: Of paramountcy to SLTs were the individual needs and preferences of their clients. Practical barriers and areas of uncertainty increased hesitance to diagnose, which may inadvertently preclude families from accessing resources. Recommendations include more widely accessible training in diagnostic practice, guidelines to support clinical decision-making, and a greater understanding of client preferences with regard to terminology and its potential relationship with social stigma.