Colour vision deficiencies may raise behavioural changes among children. This study explores the presence of any behavioural issues faced by primary schoolchildren with congenital red-green colour vision deficiency (CRGCVD). Materials and Methods:Male schoolchildren, aged 8-11 years old, from 10 randomly selected schools in Klang Valley were screened using Ishihara plates and Farnsworth D-15 test. Children with CRGCVD (study group) and without CRGCVD (control group) were asked to complete the Strength and Difficulties Questionnaire (SDQ) for children (self-report) while their class teachers completed the SDQ for teachers (teacher-report). Difficulty scores were calculated. The test categorised behaviour into 3 categories based on the difficulty scores into ‘normal’, ‘borderline’ and ‘abnormal’ behaviours. Non-parametric test was used to compare the median of difficulty scores between control group and study group. Spearman correlation was used to determine association between self-report SDQ and teacher-report SDQ. Results:A total of 134 schoolchildren were recruited in this study, of which 44 had CRGCVD and 90 were in the control group. Teacher-reported SDQ for the children were obtained from 134 teachers. No statistically significant differences (p>0.05) were noted between the total SDQ scores of children with and without CRGCVD using self-report SDQ and teacher-report SDQ. The total difficulty scores of self-report SDQ and teacher-report SDQ were poorly but significantly correlated. Teachers rated 9.09% of children with CRGCVD as falling under the ‘abnormal’ category, slightly higher than self-rated of 2.27%. Conclusion:This study found no prominent behavioural issues among schoolchildren with CRGCVD.