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The present work aims to analyze the distribution of radionuclides naturally occurring in the oil shale of the Ama Fatma coastal zone. For this purpose, using gamma-ray spectrometry, we analyzed the activity concentrations of uranium (U), thorium (Th) series, and potassium-40 (K-40) in oil shale samples retrieved from the study area. The concentrations of U-238 ranged from 45 ± 36 to 194 ± 50 Bq.kg⁻¹ and those of Th-232 fluctuated between 1.48 ± 0.92 and 9.47 ± 1.06 Bq.kg⁻¹. The measured concentrations for Ra-226, Pb-214, and K-40 oscillated between 33 ± 5 and 138 ± 9 Bq.kg⁻¹, 18 ± 1 and 68 ± 3 Bq.kg⁻¹, and between 17 ± 4 and 279 ± 16 Bq.kg⁻¹, respectively. The obtained values variation appears to be related to the deposit nature and assimilation processes of appropriate radionuclides rather than the retrieved samples’ related depth. The analysis of ²³²Th/²³⁸U and ²²⁶Ra/²³⁸U allowed an understanding of these radionuclides’ behaviors. The ratios ²²⁶Ra/²³⁸U ranged from 0.56 to 0.74 with a mean value of 0.70 which indicates the existence of disequilibrium in the investigated oil shale samples. This disequilibrium can be attributed to significant differences in the mobility of these radionuclides.