<p>This research investigates the stratigraphy, facies, and paleoenvironmental evolution of the Eocene Sequence in the Ras Al Hilal area of the Al Jabal Al Akhdar Uplift, Cyrenaica, Libya. The goal of this research is to conduct facies analyses and reconstruct the diagenetic history of the Eocene portion of the Apollonia and Darnah formations. Also, to reconstruct their paleodepositional setting. Furthermore, the stacking patterns and the sequence-stratigraphic surfaces were used to establish a sequence-stratigraphic framework for constructing regional correlations and determining the controlling factors of the studied successions. This study is based on measurements of 10 surface sections, which were described in detail, and on petrographic analysis of thin sections of rocks collected in the focus area. Six major microfacies are recognized in the studied surface sections, namely chalky-mudstone, algal nummulitic-packstone, fossiliferous-grainstone, nummulitic-packstone, fossiliferous-rudstone, and nummulitic-grainstone. This study indicated that the Apollonia and Darnah formations differ in facies but were deposited in the same epoch. The presence of post-depositional modifications, including micritization in mudstone microfacies and cementation and dissolution in packstone, grainstone, and rudstone microfacies, indicates marine phreatic diagenesis in all facies. Partial cement dissolution has resulted in enhanced secondary porosity at shallower depths. Mechanical compaction, increasing blocky calcite cementation, quartz replacement, recrystallization, and chertification occurred during deep burial. Two main depositional environments were interpreted: (1) a deep marine setting corresponding to the middle to toe of the slope, represented by the chalky limestones of the Apollonia Formation; (2) a shallow marine foreslope environment composed mainly of nummulitic limestones of the Darnah Formation. The depositional environment model for the studied Eocene sections illustrates the interfingering relationship between the two formations, as indicated by vertical repetitive coarsening upward cycles (shallowing-upward sequence), and of lateral equivalent; at any point in the Eocene time the shallower-water facies of the Darnah Formation (to the east and closer to the paleoshore-line) passes laterally into the deeper-water facies of the Apollonia Formation (to the west further offshore). This transition is primarily influenced by sea-level changes, tectonic, and topographic relief. The interpreted interfingering between the studied Apollonia and Darnah formations may indicate a diachronous relationship, driven by shoreline advances (transgression) and retreats (regression) through time. Two superimposed depositional sequences of the 3rd order, divided by conformable contact, comprised the examined Eocene carbonate successions. A retrogradation (deepening upward)-progradation (shallowing upward) unit consistently sets up each rock unit. The correlation between Eocene sequences in the Mediterranean emphasizes the interaction between tectonic and eustatic sea-level fluctuations and additional factors, such as topography and subsidence, in the formation of Eocene successions during the Late Ypresian/Early Lutetian.</p>