  The Standard Model Effective Field Theory (SMEFT) provides a systematic and
model-independent framework to study neutrino non-standard interactions (NSIs).
We study the constraining power of the on-going neutrino oscillation
experiments T2K, NO$\nu$A, Daya Bay, Double Chooz and RENO in the SMEFT
framework. A full consideration of matching is provided between different
effective field theories and the renormalization group running at different
scales, filling the gap between the low-energy neutrino oscillation experiments
and SMEFT at the UV scale. We first illustrate our method with a top-down
approach in a simplified scalar leptoquark model, showing more stringent
constraints from the neutrino oscillation experiments compared to collider
studies. We then provide a bottom-up study on individual dimension-6 SMEFT
operators and find NSIs in neutrino experiments already sensitive to new
physics at $\sim$20 TeV when the Wilson coefficients are fixed at unity. We
also investigate the correlation among multiple operators at the UV scale and
find it could change the constraints on SMEFT operators by several orders of
magnitude compared with when only one operator is considered. Furthermore, we
find that accelerator and reactor neutrino experiments are sensitive to
different SMEFT operators, which highlights the complementarity of the two
experiment types.
