This study presents a comprehensive investigation into the effects of harmonic distortions on the energy measurement accuracy of smart electricity meters. Given the prevalence of non-linear loads in modern electrical systems, understanding the impact of harmonics on energy metering is crucial for ensuring accurate billing and system reliability. In the present work, experiments have been conducted on smart energy meters using, programmable power sources, to create a range of harmonic conditions and measurement of meter accuracy under the presence of harmonics disorders with two reference meters carried out for validation of the results. The experimental procedure involved generating pure sine waves and introducing various harmonics (3rd, 5th, 7th, 11th, etc.) in the supply system subsequently, measuring the resultant energy with the smart meters. Comparative analyses were performed against true RMS readings to evaluate the meters’ accuracy under distorted waveforms. The results demonstrate a significant deviation in the meter readings with increasing harmonic frequency, amplitude, and phase angle underscoring the susceptibility of metering technology to harmonic distortion.