This dissertation explores the expression of counterfactuality crosslinguistically, both from a morpho-syntactic/semantic perspective - focusing on the interaction between tense, aspect, mood and modality - and from a semantic/pragmatic perspective - focusing on the presuppositions and implicatures of counterfactual conditionals.Through special emphasis on Palestinian Arabic, this dissertation contributes an enlightening perspective on the typological dimension of counterfactuals. By offering a description and analysis of novel data, this dissertation shows that the relative morpho-syntactic transparency with which Palestinian Arabic expresses counterfactuals offers an illuminating view on puzzling crosslinguistic data. In doing so, this dissertation sheds light on and helps discriminate among existing accounts of counterfactuality. This dissertation also adds clarity to the semantic dimension of counterfactuals by proposing a compositional/dynamic account that might be crosslinguistically unifying for counterfactual conditionals and their use in context.This study is of interest to scholars concerned with issues related to the typology, syntax, and semantics of counterfactual conditionals, as well as those involved in the inquiry into the syntax/semantics interface in the tradition of Generative Grammar or those interested in Dynamic Semantics.