Studies on Subject Pronoun Expression (SPE) in the Portuguese-speaking world have shown a distinction between European Portuguese, which is a Null Subject Language (NSL) with high rates of null subjects, and Brazilian Portuguese, which is controversially treated as a partial-NSL and exhibits a considerably lower rate of null subjects. No specific studies have been conducted on the matter on Santomean Portuguese, but we know that both null and overt subject personal pronouns exist in this variety of Portuguese. The objective of this paper is to investigate variation in SPE in Santomean Portuguese, and to situate this variety of Portuguese in comparison with other varieties. Results of the variationist analyses show that Santomean Portuguese patterns more like European Portuguese in its high rate of use of null subject. Interestingly, and contrary to previous studies, Santomeans with a higher level of education disfavor the use of null subject, which I relate to a sensitivity to grammatical ideology and the favoring of the overt subject in more formal situations. Most of the results regarding the linguistic predictors, which are stronger than the social predictors, relate Santomean Portuguese to other varieties of Portuguese, and to Spanish.