Abstract The assessment of disease activity in paediatric morphoea is challenging. Clinical examination and the Localized Scleroderma Cutaneous Assessment Tool (LoSCAT) are subjective. Thermography is the monitoring tool of choice but has a high rate of false-positive results, with low specificity. Multispectral imaging (measuring depth, volume, haemoglobin and melanin) may provide a noninvasive objective assessment of disease activity. The aim of this study was to compare activity assessment with multispectral imaging vs. clinical assessment in children with morphoea. 3D images of site-matched affected and unaffected skin were obtained using a handheld portable Antera 3D camera (Miravex Ltd). Analysis of depth, volume, haemoglobin and melanin was performed using the Antera Clinical Studies software. Objective and subjective clinical assessment was performed using LoSCAT and Children's Dermatology Life Quality Index (CDLQI). To date, 17 children (age range 7–18 years) have been recruited. Two-thirds (65%) had linear morphoea and 58% were treated with systemic agents (pulsed methylprednisolone, methotrexate, mycophenolate mofetil, abatacept). Average LoSCAT scores were 20.6 (range 5–73), and average CDLQI scores were 3.7 (range 0–14). The average haemoglobin gradient between affected and unaffected skin was 0.3 in children with active disease and 0.08 in those who had persistent disease remission (P < 0.0001). The sensitivity of multispectral imaging in paediatric morphoea is 90% with specificity of 100%, giving a positive predictive value of 100%, and a negative predictive value of 95%. Multispectral imaging of affected skin may aid activity detection in paediatric morphoea and is particularly useful in darkly pigmented skin.