Introduction: 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. Nonparametric 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.