The prevailing opinion regarding Gallo-Roman religion, expressed by Jullian, Hubert, Thévenot, Duval, Hatt and Wightman, is that it was a fusion between the two religions. Scholars who dissent from this view can be divided into two different groups. On the one hand, Woolf contends that, during a formative period of Gallo-Roman civilisation, there was a partial abandonment of the Gallic rites, that Roman religion came to be understood to be better as well as different, and that Gallo-Roman religion offered more spiritually as well as materially. On the other hand, Vendryes, Le Roux, Guyonvarc’h and Benoît hold that the Gallic deities continued to be worshipped, some under a Roman guise, others in their original pre-Roman form; however, they accept aniconism, atectonism and the reports that the Romans stopped human sacrifice and headhunting. I agree, for the most part, with Vendryes, Le Roux, Guyonvarc’h and Benoît, but directly oppose Woolf. I argue, not only that the worship of the Gallic deities continued, but also that Gallic religion already made use of anthropomorphic images and formal structures before the Roman Conquest, that the disappearance of human sacrifice was wrongly attributed to the Romans and that the Romans never suppressed headhunting. In chapter one I discuss some conceptual problems that need clarification before the subject can be properly addressed. They include problems regarding terminology, presuppositions and errors. In the second chapter I refute the concept of aniconism and examine the archaeological and literary sources of information about Gallic religion and their reliability. Using these sources, in the third chapter, I identify Gallic deities and decode the enigma of the pantheon set out by Caesar. In the fourth chapter I dismantle the myth of atectonism and confirm the use of formal structures of worship and ritual by the Gauls; I also analyse the essential elements of such structures, supporting my argument by a comparison of pre-Roman Celtic sanctuaries from both inside and outside the Roman Empire. In the fifth chapter I examine the concept of sacrifice from an anthropological perspective and apply this approach to all Gallic sacrifices; I also examine the Gallic rituals of divination and circumambulation. I establish the basis for the magico-religious significance and popularity of headhunting in the sixth chapter. In the seventh chapter I define the Celtic belief in an Afterlife and demonstrate its attraction. Finally, in the eighth chapter, I examine how many of these Gallic beliefs and customs continued after the Roman Conquest and demonstrate that Gallic religion was not abandoned, that the Celtic sanctuary design was the basis for Gallo-Roman temple design and that the Gallo-Roman religion was far more Gallic than Roman.