There is a scarcity of research exploring the field of Speech and Language Disorders (SLD) in the Greek mainstream primary education context. Accordingly, the aim of this study was twofold: (i) to identify the nature and extent of speech, language and communication skills of Greek pupils with noticeably slow progress, and (ii) to examine the provision made for these pupils in Greek mainstream and inclusion classes. The study was in two phases. For the first phase, pupils whose speech and language development was below expectations were assessed using a battery of tests. Data analysis indicated no significant differences in the language profile and non-verbal reasoning ability of the pupils with SLD, General Learning Difficulties (GLD) and other Special Educational Needs (SEN). The data also gave an indication of SLD incidence in Greek mainstream primary classrooms. Phase two involved seven case studies. Together, these provided a rich profile of the speech/language and literacy functioning of the pupils identified with SLD, GLD and Specific Writing difficulties (SpWd) and the provision offered to them in Greek primary mainstream settings. The findings revealed that these pupils shared difficulties in the domains of speech/language and literacy, which impacted on their access to the curriculum and academic attainments. However, teaching practices were not differentiated according to the pupils’ specific needs or year group. Additionally, pupils’ difficulties in the above areas had a negative impact on their social participation and acceptance by peers. Overall, the study highlights the complex nature of SLD, and the similarities in the language profile and the non-verbal reasoning skills of the SLD and other SEN subgroups. This raised questions about whether SLD, as used in these schools, is a distinct area of difficulty or on a continuum with other areas of difficulties. In addition, the study raised questions regarding the assessment and identification of SLD in the Greek context, as well as the practical teaching of pupils who experience such difficulties.