Bolzano's theory of objective ground and consequence is part of a general account of a priori knowledge and a theory of demonstration or proof — note here that I do not use the term "proof theory' which Bolzano's theory is not — that has attracted some attention in recent years. When it comes to explaining the nature of deductive knowledge at large, Bolzano distinguishes between three notions: grounding (Abfolge), objective justification (objective Erkenntnisgrund) and what we may call objective demonstrations or proofs, which Bolzano calls Begründungen. This tripartite distinction in itself testifies to Bolzano's refined sense for the differences between logical, epistemological and pragmatic concerns: grounding is a relation between true propositions; objective justification is a relation between beliefs or cognitions (i.e., certain types of epistemic states); and Begründungen are linguistic objects that are meant, according to Bolzano, to reliably cause in agents objectively justified knowledge of the type we find in a priori sciences such as mathematics. Roughly, the structure of the theory is the following: (i) grounding is a relation that subsists, according to Bolzano, between true propositions independently of epistemic access to them. We may grasp grounding relations and (ii) our grasping the latter is also the condition for our having objective justifications for our beliefs, as opposed to, say, merely subjective or evidential ones.