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The simplest neutrino mass models based on $A_4$ symmetry predict$\theta_{13} = 0$ at tree level, a value that contradicts recent data. We studymodels that arise from the spontaneous breaking of an $SO(3)$ symmetry to its$A_4$ subgroup, and find that such models can naturally accommodate a nonzero$\theta_{13}$ at tree level. Standard Model charged leptons mix with additionalheavy ones to generate a $\theta_{13}$ that scales with the ratio of the$A_4$-breaking to $SO(3)$-breaking scales. A suitable choice of energy scaleshence allows one to reproduce the correct lepton mixing angles. We alsoconsider an alternative approach where we modify the alignment of flavonsassociated with the charged lepton masses, and find that the effects on$\theta_{13}$ are enhanced by a factor that scales as $m_\tau/m_\mu$.

Nonzero $\theta_{13}$ in $SO(3) \rightarrow A_4$ lepton models