Primary teacher training programmes in New Zealand do not provide training about specific communication disorders (SCDs), despite prevalence of SCDs of approximately 7%. This pilot study investigated the effectiveness of a three-hour professional development (PD) programme for a specialised group of primary teachers, Special Education Needs Coordinators (SENCOs), around working with children with SCDs in the classroom. Six SENCOs from different schools participated. Effectiveness was measured using a pre-test/post-test within-subjects design. Outcome measures were (1) a knowledge questionnaire and (2) a videoed interaction with a new-entrant child. SENCOs increased the specificity of responses to open questions and improved their scores on closed questions, with a significant improvement in knowledge about characteristics of the children. Eleven strategies were counted in the videoed interactions; seven improved and two deteriorated. SENCOs reported satisfaction with programme content and length. Additional research is recommended to further develop the PD programme into an effective resource for classroom teachers. (Contains 4 tables.)