This dataset contains bioenergetics data generated from undifferentiated and differentiated HepaRG cell culture models following mono(2-ethylhexyl) phthalate (MEHP) treatment. Data include normalized Seahorse XFp Mito Stress Test measurements, including oxygen consumption rate (OCR) and extracellular acidification rate (ECAR), provided as structured comma-separated value (.csv) files. The dataset includes experimental variables such as treatment condition (MEHP/plus vs. vehicle/minus), cell differentiation state, time point, and normalized quantitative measurements with associated units. These data support analysis of mitochondrial bioenergetics under toxicant exposure conditions and are suitable for reanalysis. Associated experimental outputs, including western blot and Southern blot image data used to assess protein expression and mitochondrial DNA (mtDNA) stability, are available via the linked Zenodo repository. No human subjects data are included. All data are de-identified and shared under CC0 (Dryad), with associated image files available under CC BY (Zenodo).