Background Dental pain exerts a considerable impact on the psychosocial well‐being of children; reliable management of pain depends on the ability to assess pain intensity. Aim To validate and compare a new memojis pain assessment scale with the Faces Pain Scale—Revised (FPS‐R) and Wong–Baker FACES Pain Rating Scale (WBFPS) in assessing dental pain experienced by children. Design Two hundred and fifty healthy children aged 5–9 years without any past dental experience and requiring local anaesthesia (LA) administration were recruited. Three different scales [FPS‐R, WBFPS and Memojis Pain Scale (MPS)] were applied to assess the children's pain during LA administration. The preferences of each child based on the ease of understanding the faces were recorded. Results Pearson correlation test was performed to determine the correlation between MPS with WBFPS and MPS with FPS‐R. A strong correlation was seen when comparing MPS with WBFPS (r = .966; p < .001) and MPS with FPS‐R (r = .969; p < .001), and 81.6% of the children preferred MPS. Conclusion The Memojis Pain Scale was an effective pain assessment tool. It can be employed as an alternative scale for pain assessment in children.