Susagna Tubau's main line of research is embedded within the field of theoretical linguistics and, in particular, syntax. Tubau is interested in how single negation, Double Negation and Negative Concord are expressed in natural languages, with special emphasis on the variability that is observed across non-standard varieties of English. 

Tubau has also researched other linguistic phenomena related to negation in natural languages, such as expletive negation, the nature of yes/no answers, the syntax of minimizers, the limits of polarity and negative concord, the diachronic development of negated adjuncts and the compositionality of negative quantifiers.

Other secondary research lines parallel to Tubau's main one are (native and foreign) language acquisition, the that-trace effect in English and the linguistic expression of gender in texts translated from English to Catalan and Spanish.

-24 journal articles (20 in journals indexed in Journal Citation Reports, Social Science Citation Index and 4 indexed in CARHUS Plus, ERIH and/or other), 9 book chapters, 9 conference proceedings and 2 reviews.

-Positive evaluation of two six-year research periods by the Agència de la Qualitat del Sistema Universitari de Catalunya (AQU).

-Member of 6 funded research projects and 2 Thematic Networks of Excellency.

-Member of the consolidated research group Grup de Lingüística Teòrica, funded by Generalitat de Catalunya.

-Speaker in more than 40 conferences in the field of linguistics.

-Reviewer for several national and international journals, the scholarship programme of La Caixa-British Council for postgraduate studies in Europe and Asia-Pacific, and the research project programme of the National Science Foundation (United States).