In his 1794 Grundlage der gesammten Wissenschaftslehre Fichte makes a number of remarks about Spinoza that, at first, might seem to be contradictory: On the one hand, he describes Spinozism as a form of dogmatism that is fundamentally opposed to the critical philosophy of the Wissenschaftslehre (WL). On the other hand, he states that the theoretical part of the WL is systematic Spinozism. Fichte himself points to the practical part of the WL to solve the conceptual tension between these two claims. In this essay, I try to reconstruct the connection between Fichte’s criticism of Spinoza and the practical WL as it can be extracted from the Grundlage. In this reconstruction, the two-fold practical meaning of the first foundational principle of the WL plays a crucial role: It is key to the understanding Fichte’s ultimately decisive rejection of Spinozism.