Temperature dependent in-plane impedance spectroscopy measurements were carried out in order to analyze the charge transport properties of functional oxide NiMn2O4 negative temperature coefficient thermistor films deposited via aerosol deposition techniques onto glass and Al2O3 substrates. The in-plane resistivity (ρ) versus temperature (T) curves of all films were uniform over a large temperature range (180 K to 500 K) and showed the typical exponential power-law behavior associated with variable-range hopping. The ρ-T dependences of annealed and as-deposited films exhibited power-law exponents p of about 0.6 and thermistor constants B in the range of 3500 K to 5000 K. As-deposited films showed higher p values as compared to annealed films. As-deposited films exhibited also increased B values, leading to increased sensitivity of the resistance to temperature changes, whereas annealed films deposited on Al2O3 showed the lowest scatter in differentiated ρ-T data and might display superior reliability for temperature sensing applications.