I present an analysis of Tashlhiyt Berber meter, based on the corpus of ‘straight’ meters collected and analyzed by Dell and Elmedlaoui (2008). There are 56 meters (35 independent, 21 dependent), which are systematically related to each other. Based on the many shared properties of all straight meters and their individual inflexibility, I suggest that they all derive from the same general metrical template, much in the same way as proposed by Deo (2007) for several Sanskrit meters. The individual meters are thus different realizations of the general meter, where the modulation of line length is part of the realizational variation (unlike the case in Sanskrit). I also argue that the generalizations pertaining to the system of meters can be better understood, and more broadly formulated, in terms of the phonology of the language, in three areas. First, the Tashlhiyt straight meters are rhythmic in a very specific sense: they all obey NO CLASH . Several previously unconnected facts—verse foot shapes, avoidance of two heavy syllables in sequence, and the regular alternation of verse feet—follow from this single fact. Second, the meters are pervasively binary, with a strong preference for tetrameter, a fact that is not predicted by models where line length is stipulated (e.g. Hanson and Kiparsky 1996; Fabb and Halle 2008). Line length tendencies follow from the linguistic constraints on binarity, under the assumption that metrical templates are derived from the prosodic hierarchy, rather than externally, e.g. from a specific meter-generating module (e.g. Kiparsky 1977; Blumenfeld 2015). This would indicate that meter is derived from grammar in just the same way as prosodic morphemes. Third, and related to the second point, the regular prosody and the meter are simultaneously present in a line of verse, a common assumption. However, the fact that both structures come out of the linguistic grammar means that grammar operates in both domains (like in root-and-pattern morphology), rather than there being a matching between them. Meter obeys some constraint to a higher degree than does regular prosody, instantiating overall improvement in the particular respect addressed by the chosen constraint. In the straight meters of Tashlhiyt Berber, this privileged constraint is NO CLASH (as also in Tegnér’s Swedish hexameter), whereas in other systems the constraint may concern e.g. the alignment of prominence at some level (Darío’s Spanish alexandrines, Strindberg’s Swedish hexameter).