This paper aims to provide a Labovian sociolinguistic description of 3rd person plural patterns of agreement in European (EP), Brazilian (BP) and São Tomé (STP) Portuguese based on very recent samples of speech stratified for age, sex/gender and education. Linguistic and social restrictions for the variation are investigated. Results from statistical analysis indicate that there are two patterns of agreement in Portuguese: a semi-categorical rule, typical of EP, and a variable rule, typical of BP and STP, restricted by specific linguistic and social factors. Additionally, the results indicate that general linguistic constraints – such as the position of the subject, semantic feature of the subject or even discursive parallelism – cannot say anything about historical origin of Portuguese varieties, since they can be concerned with any language. Therefore, besides the quantitative expression of non-agreement, the quality of the occurrences of non-plural marking may support the characterization of each variety.