Luminescent thermometers based on transition metal and lanthanide ion codoped nanocrystals have become a group of non-contact thermometers which are gaining importance due to their high sensitivity upon temperature changes. Here we present two types of luminescent thermometers, namely, bandshape and lifetime temperature sensors based on Y3Al5O12:Mn3+,Mn4+,Nd3+ nanocrystals. Their ability for temperature sensing was investigated as a function of Mn concentration. It was found that both sensitivity and usable temperature range depend on the Mn concentration. The highest sensitivity (S = 2.69%/K) was found for the lifetime luminescent thermometer with 0.01%Mn concentration and its value is gradually reduced with Mn content. Similarly, in the case of the bandshape luminescent thermometer, the sensitivity decreases from 1.69%/K for 0.01%Mn to 0.54%/K for 1%Mn. On the other hand the usable temperature range extends with dopant concentration. The concentration effect on the temperature dependent optical parameters is discussed in terms of interionic interactions facilitated for shorter Mn-Mn distances.