The aim of this study was to adapt the knee and hip osteoarthritis quality of life questionnaire (OAKHQoL) into Moroccan Arabic and to determine its psychometric properties. After translation, back-translation and pretesting, the translated version was submitted to an expert committee. The psychometric properties were tested on patients with hip or knee osteoarthritis. Internal consistency was tested using Cronbach's alpha coefficient (α), and the test-retest reliability using intraclass correlation coefficients (ICC). Construct validity was assessed by examining item-convergent and divergent validity and by comparing the average scores between age groups and walk perimeter groups. The study was conducted on 131 patients (115 with osteoarthritis of the knee and 16 with osteoarthritis of the hip). The "physical activities" (α = 0.93), "mental health" (α = 0.84) and "pain" (α = 0.88) dimensions of the Arabic version were internally reliable. The ICC were adequate to good; 0.83 for "physical activities", 0.65 for "mental health" and 0.70 for "pain" dimensions. The instrument demonstrated good construct validity; all items exceeded the 0.4 criterion for convergent validity, except items 13 and 41 and most of the correlations between items and their own scale were significantly higher than their correlations with other scales. A semantically equivalent translation has been developed with cultural adaptation of OAKHQoL. It is quite reliable and a valid measure of the effect of osteoarthritis on the quality of life on Moroccan patients.