The global expansion of olive cultivation has led to the widespread adoption of highly mechanized production systems, with the Arbequina cultivar emerging as a dominant choice due to its high productivity and adaptability. Given that the physicochemical quality of its oil is highly sensitive to environmental conditions, understanding the impact of abiotic stress on olive oil quality during key fruit developmental stages is essential for adapting orchard management to climate variability. In this context, the aim of this study was to identify and characterize the critical periods of fruit development that determine the physicochemical quality, fatty acid composition, and phenolic profile of 'Arbequina' olive oil under conditions of reduced solar radiation. To this end, whole olive trees were subjected, to intense shading (80%) during 30-day periods, using chambers. The results revealed that oil composition, particularly oleic acid content, and extinction coefficients are significantly influenced by the timing of stress exposure. Besides, two key accumulation phases of the principal fatty acid, cis-oleic acid were identified: an early phase (30-60 days after full bloom, DAFB) marked by increased content, and a later phase (120 DAFB) showing a pronounced decline. These changes were inversely correlated with palmitic acid levels. Linoleic acid levels decreased significantly during the 30-60 DAFB, while linolenic acid levels declined between full bloom and 30 DAFB, followed by an increase after 90 DAFB. Regarding phenolic compounds, oleacein and oleocanthal levels decreased significantly under stress, whereas hydroxytyrosol and luteolin remained stable, indicating selective metabolic responses. Given the global expansion of olive cultivation in semi-arid regions, these findings provide a framework to mitigate climate-induced quality losses in a wide variety of emerging production areas. By identifying stress-sensitive developmental stages, this study offers actionable insights to preserve EVOO quality and optimize harvest and canopy management. L'expansion mondiale de la culture de l'olivier a conduit & agrave; l'adoption g & eacute;n & eacute;ralis & eacute;e de syst & egrave;mes de production hautement m & eacute;canis & eacute;s, la vari & eacute;t & eacute; Arbequina s'imposant comme un choix dominant en raison de sa forte productivit & eacute; et de son adaptabilit & eacute;. & Eacute;tant donn & eacute; que la qualit & eacute; physicochimique de son huile est tr & egrave;s sensible aux conditions environnementales, il est essentiel de comprendre l'impact des stress abiotiques sur la qualit & eacute; de l'huile d'olive durant les principales phases de d & eacute;veloppement du fruit afin d'adapter la gestion des vergers & agrave; la variabilit & eacute; climatique. Dans ce contexte, l'objectif de cette & eacute;tude & eacute;tait d'identifier et de caract & eacute;riser les p & eacute;riodes critiques du d & eacute;veloppement du fruit qui d & eacute;terminent la qualit & eacute; physicochimique, la composition en acides gras et le profil ph & eacute;nolique de l'huile d'olive 'Arbequina' dans des conditions de rayonnement solaire r & eacute;duit. & Agrave; cette fin, des oliviers entiers ont & eacute;t & eacute; soumis & agrave; un ombrage intense (80 %) pendant des p & eacute;riodes de 30 jours, & agrave; l'aide de chambres.Les r & eacute;sultats ont r & eacute;v & eacute;l & eacute; que la composition de l'huile, en particulier la teneur en acide ol & eacute;ique, ainsi que les coefficients d'extinction, est significativement influenc & eacute;e par le moment d'exposition au stress. Par ailleurs, deux phases cl & eacute;s d'accumulation du principal acide gras, l'acide ol & eacute;ique cis, ont & eacute;t & eacute; identifi & eacute;es : une phase pr & eacute;coce (30-60 jours apr & egrave;s la pleine floraison, DAFB) caract & eacute;ris & eacute;e par une augmentation de la teneur, et une phase plus tardive (120 DAFB) marqu & eacute;e par un d & eacute;clin prononc & eacute;. Ces variations & eacute;taient inversement corr & eacute;l & eacute;es aux niveaux d'acide palmitique. Les niveaux d'acide linol & eacute;ique ont diminu & eacute; significativement entre 30 et 60 DAFB, tandis que ceux d'acide linol & eacute;nique ont diminu & eacute; entre la pleine floraison et 30 DAFB, avant d'augmenter apr & egrave;s 90 DAFB. Concernant les compos & eacute;s ph & eacute;noliques, les teneurs en ol & eacute;ac & eacute;ine et en ol & eacute;ocanthal ont diminu & eacute; significativement sous stress, alors que l'hydroxytyrosol et la lut & eacute;oline sont rest & eacute;s stables, indiquant des r & eacute;ponses m & eacute;taboliques s & eacute;lectives. Compte tenu de l'expansion mondiale de la culture de l'olivier dans les r & eacute;gions semi-arides, ces r & eacute;sultats fournissent un cadre permettant d'att & eacute;nuer les pertes de qualit & eacute; induites par le climat dans un large & eacute;ventail de zones de production & eacute;mergentes. En identifiant les stades de d & eacute;veloppement sensibles au stress, cette & eacute;tude apporte des & eacute;l & eacute;ments concrets pour pr & eacute;server la qualit & eacute; de l'huile d'olive vierge extra (EVOO) et optimiser la gestion de la r & eacute;colte et de la canop & eacute;e.