In this course I will introduce some generalisations of matroids and Hamming metric codes, called q-matroids and rank-metric codes, respectively. These generalisations are examples of q-analogues, where a combinatorial structure defined in relation to a set is instead associated with a vector space. There are many connections between codes and matroids and similarly many connections between rank-metric codes and q-matroids. We will look at different equivalent ways of defining a q-matroid and see how these compare with their classical counterparts. We will also introduce some q-matroid invariants and see how these give invariants of rank-metric codes.