Of course, the syllabus content is different for Maths HL and Maths SL. In addition to this very important difference, what are the other essential differences between Maths HL and Maths SL? Perhaps the most significant difference between HL and SL is encapsulated best with a single word: rigour (rigor in the US). The HL course is definitely more rigourous than the SL course - but describing in words what this means...