Yes, it may be able to. At least, Delphi, the idea (and language) of which Lazarus is based on, was written in itself, at least for v1, I've read. Probably for later versions too, because Object Pascal (although IIRC the language is now called Delphi, like the product), is a powerful general-purpose programming language, with OOP support, module (units) support, and even some sort of generics (IIRC) in later versions.