<p>Photosynthetic responses to persistent moderate water stress were examined in four-year-old seedlings of two Tunisian cork oak (<i>Quercus suber</i> L.) provenances with contrasting climatic origins. “Gaafour” was the provenance originating from the driest site, while “Feija” was from the wettest. Under 7–10% volumetric soil water content (<i>SWC</i>, %), both provenances exhibited lower photosynthetic activity, stomatal conductance (<i>g</i>s) and a decrease in relative water content (<i>RWC</i>) to 52% compared to well-watered controls. Despite similar stomatal conductance (<i>g</i>s) and intracellular CO₂ concentration (<i>C</i>i) in “Feija” and “Gaafour” stressed leaves, net photosynthesis was higher in “Gaafour”. Chlorophyll content and specific leaf area (<i>SLA</i>) were not influenced by drought treatment. Drought stress increased the light compensation point (<i>LCP</i>) in “Feija” and “Gaafour” stressed leaves, but more pronouncedly in “Feija”. However, the apparent quantum yield (Φ) decreased only in “Feija” stressed leaves, indicating that carbon assimilation of “Feija” stressed leaves is impaired by reduced Φ in addition to limited CO₂ diffusion. These results show the existence of provenance-level differentiation in cork oak and seedlings from different provenances can differ in their response to water availability during the critical phase of establishment, which could influence forest dynamics. The choice of provenance in reforestation efforts can thus have significant socio-economic implications, as selecting drought-tolerant provenances such as ‘Gaafour’ may enhance forest resilience, promote sustainable cork production, and contribute to the livelihoods of communities reliant on these ecosystems.</p>