This paper presents the construction of the SES-SACMEQ scale as a measure of the socioceconomic status (SES) of pupils in primary education for the Southern and Eastern Africa Consortium for Monitoring Educational Quality (SACMEQ). The scale, based on eighteen items, was constructed using the Rasch scaling technique. The scores on the SES-SACMEQ of over 60 000 pupils were analyzed in order to establish profiles (expected responses on the 18 items) by country. A positive correlation between the SES of the pupils and their achievements in reading and mathematics was found for most of the countries.