We present a resonant x-ray scattering study of the octahedral tilt order between 50 K and 310 K in La7 8 Sr1 8 Mn O3. At the La LII -edge, the resonant (300) reflection probes cooperative tilts of the Mn O6 octahedra in this material, as verified by a model caclulation as well as a LDA+U study. The investigation of the octahedral tilts as a function of temperature and the comparison to the lattice parameters, the magnetization and the superlattice reflections related to charge and/or orbital order reveal an intimate coupling between electronic and tilt degrees of freedom in La7 8 Sr1 8 Mn O3.