The second-century bce Libyco-Berber inscriptions from Dougga (present-day Tunisia) have seven different signs for sibilants. In this article the sibilant system of these inscriptions and of the language they represent is studied in detail. It is shown that the different signs are not just graphemic variants but represent different pronunciations. It is also shown that there is a possibility that the seven signs in fact represent three or four articulations with a length contrast, even though the evidence is very weak. As Proto-Berber has been reconstructed with only three sibilants (+ length opposition), the choice of how to analyze the seven Libyco-Berber sibilant signs has important implications as to how the relationship between Libyco-Berber and Proto-Berber is to be assessed.