This case study explores the dynamic nature of teacher motivation within the context of socio-educational disparities--an area that remains underexplored in language education research. Framed within Complex Dynamic Systems Theory, the study examines the motivational experiences of a highly experienced English language teacher who voluntarily participated in the research. Data were collected through weekly self-ratings and reflective journals over a five-week period, complemented by a semi-structured interview conducted at the end of the data collection phase. The findings reveal that teacher motivation exhibits stability and variability, fluctuating within and across instructional sessions due to an intricate interplay of teacher- and learner-related factors. The results demonstrate that teacher motivation is highly sensitive to micro-level changes and is shaped by both in-class and out-of-class conditions. Additionally, socio-educational disparities, particularly socioeconomic and geographical factors, emerged as significant demotivating influences, underscoring the impact of contextual constraints on professional engagement. These insights highlight the need for targeted support and context-responsive policy interventions to mitigate the adverse effects of structural inequalities on teacher motivation in under-resourced educational settings.