Phonological awareness is closely related to reading acquisition and it is often the focus of the therapy services provided by speech-language pathologists and special education teachers. In this study, we investigate whether sonority theory can account for the developmental patterns of phoneme awareness skills in Greek. To that end, 40 preschool and first grade children carried out an offline metaphonological task that involved the initial consonant deletion of two-consonant clusters. Overall, children's performance was in line with the sonority sequencing principle (SSP); consonant clusters that display a maximal rise in sonority were easier to manipulate compared to clusters with minimal sonority difference or SSP-violating clusters. Affricates generated the highest number of errors, a finding that strengthens the singleton status of /ts/ and /dz/ in Greek. Increased error rates were also found for /ps/, /pç/, /ks/, a fact attributed to both to their spelling and sonority characteristics. Conclusively, it is claimed that the developmental error patterns reported in this study can be used to inform appraisal and treatment protocols of phonological awareness in Greek, by organizing metaphonological tasks based on the presumed level of difficulty of the items tested and/or treated.