The present study examines the psychometric properties of the long form (LF) of the Greek translation of the Friendship Quality Questionnaire (FQQ), a widely recognized self-report instrument that assesses children's perceptions of the qualities of their friendships. Four hundred seventeen (417) typically developing primary-school students (50.8% boys), aged between 8 and 12 years (M = 9.77 years old, SD = 1.2), who had a mutual best friend in their class, completed the survey at school. Confirmatory factor analysis verified the six-factor structure of the original FQQ with all items fitting into the respective subscales. All factors presented high positive intercorrelations except for the Conflict and Betrayal subscale. All subscales demonstrated adequate internal consistency. Significant gender differences were observed. The Greek translation of the FQQ-LF shows strong evidence of validity and reliability and provides a suitable instrument for assessing the qualitative characteristics of best friendships.