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Several experiments have measured a deviation in $B\to D^{(*)}$ semileptonicdecays, that point to new physics at the TeV scale violating lepton flavoruniversality. A scalar leptoquark $S_1$ is known to be able to solve thisanomaly modifying $b\to c\tau\bar\nu$. In the context of composite Higgsmodels, we consider a theory containing $H$ and $S_1$ as Nambu-Goldstone bosons(NGBs) of a new strongly interacting sector, with ordinary resonances at ascale ${\cal O}(10)$ TeV. Assuming anarchic partial compositeness of theStandard Model (SM) fermions we calculate the potential of the NGBs that isdominated by the fermions of the third generation, we compute $R_{D^{(*)}}$ andestimate the corrections to flavor observables by the presence of $S_1$. Wefind that the SM spectrum and $m_{S_1}\sim$ TeV can be obtained with a NGBdecay constant of order $\sim 5$ TeV, simultaneously reproducing the deviationin $R_{D^{(*)}}$. We find that the bounds on the flavor observables$B_{K^{(*)}\nu\nu}$, $g_\tau^W$, BR$(\tau\to\mu\gamma)$ and $\Delta m_{B_s}$are saturated, with the first two requiring a coupling between resonances$g_*\lesssim 2$, whereas the third one demands $m_{S_1}\gtrsim 1.7$ TeV, up tocorrections of ${\cal O}(1)$.

$b\to c\tau\bar\nu$ anomaly from a minimal composite $S_1$ leptoquark