The traits linked to gifted children with learning disabilities (twice-exceptional) are diverse and complex. Identification of these children can be hindered by a combination of factors, including variations in teacher knowledge and experience, inconsistencies in the visibility of high abilities coexisting simultaneously with one or more learning disabilities, and also the lack of a practical assessment tool. This mixed-methods study addresses the need for such a tool and other assessment strategies that primary school teachers can implement in the preliminary exploratory stage of identifying possible twice-exceptional children. In this process, the focus centres on learning strengths and difficulties. The first phase of the Study focused on procedures leading to the development and trialling of a comprehensive and useful teacher checklist questionnaire (TCQ). Its comprehensiveness was developed through reviewing research-based characteristics, anecdotal lists and teacher perceptions. Section A of the TCQ is based on the six natural-ability Domains found in Françoys Gagné's Differentiated Model of Giftedness and Talent (DMGT 2.0; 2008) or, more recently, his Expanded Model of Talent Development (EMTD, 2013). Section B has three familiar categories of learning difficulties known within the context of the primary school. In the trialling phase, ten teacher participants trialled the TCQ and ranked the selected children in their classes on every item in the nine categories. Overall, qualitative and quantitative analyses suggest promising trends in the preliminary investigation into the TCQ's internal reliability, validity and practical usefulness. In the second phase, six child participants were selected for case studies to determine whether other assessment strategies supported the findings of the TCQ. The results from Interviews with each child, a Parent/Teacher Questionnaire, a non-verbal intelligence test (Raven's Standard Progressive Matrices), and a Think-aloud protocol, affirm the worthiness of the TCQ, but variations in results suggest the importance of its inclusion as part of a comprehensive assessment protocol.