We report the negative results from a search for 6.7 GHz methanol masers in the nearby spiral galaxy M33 .
We observed 14 GMCs in the central 4 kpc of the Galaxy , and found 3 \sigma upper limits to the flux density of \sim 9 mJy in spectral channels having a velocity width of 0.069 kms ^ { -1 } .
By velocity shifting and combining the spectra from the positions observed , we obtain an effective 3 \sigma upper limit on the average emission of \sim 1mJy in a 0.25 kms ^ { -1 } channel .
These limits lie significantly below what we would expect based on our estimates of the methanol maser luminosity function in the Milky Way .
The most likely explanation for the absence of detectable methanol masers appears to be the metallicity of M33 , which is modestly less than that of the Milky Way .