Several gaps exist in the standardised assessment of pupils with Special Educational Needs and Disabilities (SEND) in the Irish mainstream education context at the point of transition from primary to post-primary school. These gaps may lead to a lack of adequate focus on the continuity of resources at this timepoint. The current study examined academic and social attainment in three cohorts of pupils in Ireland (Attention Deficit Hyperactivity Disorder, ADHD, N = 12; Mild General Learning Difficulties, MGLD, N = 12; and typically developing individuals, N = 11). Four standardised measures were used in a non-experimental design to assess cognitive attainment (Wide Range Achievements Test 4, WRAT-4), learning competency and self-concept (Myself as a Learner Scale, MALS; the Burnett Self Scale, BSS), and perceived control (Multidimensional Measure of Children's Perception of Control scale, MMCPC) across the three groups prior to transition to post-primary school. Results indicated that the typically developing pupils performed strongest on attainment followed by those with ADHD and MGLD. While the latter two groups were weaker on attainment, neither group perceived of themselves as weaker. The results are discussed within the context of formal assessment for pupils with SEND in mainstream education and how these diverse outcomes may have implications for policy.