  We present time series analyses of three-decade long radio observations of
the BL Lacertae object AO 0235+164 made at the University of Michigan Radio
Astronomical Observatory operating at three central frequencies of 4.8 GHz, 8.0
GHz and 14.5 GHz. We detected a quasi-periodic oscillation of $\sim$965 days in
all three frequency bands in the light curve of the effectively simultaneous
observations, along with strong signals at $\sim$1950 d, $\sim$1350 d, and
$\sim$660 d. The periodicity is analyzed with three methods: Data Compensated
Discrete Fourier Transform, Generalized Lomb-Scargle Periodogram and Weighted
Wavelet Z-transform. These methods are chosen as they have different analysis
approaches toward robust measurement of claimed periodicities. The QPO at
$965\pm 50$ days is found to be significant (at least $3.5\sigma$) and is
persistent throughout the observation for all three radio frequencies, and the
others, which may be harmonics, are comparably significant in at least the 8.0
GHz and 14.5 GHz bands. We briefly discuss plausible explanations for the
origin of such long and persistent periodicity.
