In research on heritage speakers, it is often observed that areas of core syntax tend to be resilient and resemble the relevant baseline. This chapter discusses this generalization and provides examples of areas that tend to be resilient and areas that are vulnerable. Research into the syntax of heritage speakers has tended to focus on certain areas, such as argument structure and the representation of null arguments, meaning that a lot of grammatical domains have not been sufficiently explored. This chapter nevertheless tries to summarize the main findings and outline important methodological and theoretical issues that any work on heritage syntax needs to consider carefully. Examples of the latter include the question of what the appropriate baseline for comparison is, and how to adequately separate morphology and syntax. Empirically, the chapter will consider lexical categories, passives, and verb second as examples of relatively resilient areas of syntactic representations. In terms of areas that are more vulnerable, it will look at word order, long-distance dependencies, and discontinuous dependencies.