BACKGROUND: Dyslipidemia is a metabolic factor associated with reproductive outcomes, but evidence on couple-level dyslipidemia in IVF/ICSI remains limited. OBJECTIVE: To investigate associations of dyslipidemia in both partners with embryological and cumulative pregnancy outcomes in couples undergoing IVF/ICSI. METHODS: This single-center retrospective cohort study included 209 infertile couples undergoing their first IVF/ICSI cycle between October 2022 and October 2025. Of these, 163 underwent fresh embryo transfer and were included in analyses of ovarian stimulation, embryological, and fresh-cycle outcomes. Cumulative outcomes were evaluated in all 209 couples using fresh and subsequent frozen-thawed embryo transfer cycles derived from the same ovarian stimulation cycle. Dyslipidemia was assessed in both partners, and couples were classified as bilateral normolipidemia, unilateral dyslipidemia, or bilateral dyslipidemia. Multivariable logistic regression and restricted cubic spline analyses were performed. RESULTS: Women with dyslipidemia had longer stimulation duration, higher total gonadotropin dose, and a lower two-pronuclear (2PN) fertilization rate. Male dyslipidemia was associated with fewer 2PN zygotes, fewer transferable embryos, and a lower 2PN fertilization rate. At the couple level, bilateral dyslipidemia appeared to be associated with less favorable embryological outcomes. After adjustment for female age, female BMI category, male BMI, and cumulative number of embryos transferred, female dyslipidemia was associated with higher odds of cumulative miscarriage (aOR = 4.455, 95% CI: 1.759-11.283) and lower odds of cumulative live birth (aOR = 0.335, 95% CI: 0.164-0.683). Male dyslipidemia was associated with lower odds of cumulative live birth (aOR = 0.309, 95% CI: 0.127-0.751). Compared with bilateral normolipidemia, bilateral dyslipidemia was associated with higher odds of cumulative miscarriage (aOR = 10.579, 95% CI: 1.830-61.174) and lower odds of cumulative live birth (aOR = 0.116, 95% CI: 0.032-0.414). RCS analyses suggested potential association patterns between selected lipid parameters and cumulative outcomes. CONCLUSIONS: Dyslipidemia in either or both partners was associated with less favorable embryological and cumulative pregnancy outcomes in IVF/ICSI cycles. Couples with bilateral dyslipidemia appeared to show less favorable outcome patterns, although these findings should be interpreted cautiously given the retrospective design and limited event numbers.