<p>To understand the relationship between sediment type and ostracod responses in complex habitats, 105 samples representing seven different habitat types were collected in August 2022 from Yozgat Province (Turkey). A total of 47 ostracod taxa were identified, 24 of which are new records for the province. Sediment type distribution differed significantly among the habitats (<i>p</i> &lt; 0.05). A significant negative correlation was found between elevation and the abundance of medium and coarse sand sediment types (<i>p</i> &lt; 0.05). There was also a significant positive correlation between the number of species and the substrate (medium sand) (<i>p</i> &lt; 0.05). However, multivariate regression models indicated that species richness was not significantly affected by sediment grain size or type (<i>p</i> &gt; 0.05). The 14 most common species tended to prefer habitats with high calcium content and medium to low water temperatures, ranging from very coarse sand (1–2&#xa0;mm) to silt-mud (40–63&#xa0;µm) sediment types. Increasing habitat complexity or the number of sampling sites did not lead to an increase in species richness. The occurrence of <i>Ilyocypris bradyi</i> varied significantly among habitats (<i>p</i> &lt; 0.05), while <i>Limnocythere inopinata</i> showed a significant negative association with muddy substrates. Canonical Correspondence Analysis (CCA) explained 84.7% of the variation in species-environment relationships, with pH emerging as the most influential variable (<i>p</i> &lt; 0.01) affecting the correlation between species and sediment types. The six most common species (<i>Heterocypris salina, H. incongruens, Ilyocypris bradyi, Cypridopsis vidua, L. inopinata, I. gibba</i>) accounted for over 73% of the variation among habitats and were frequently found in complex habitats. These results suggest that ostracod assemblages, their diversity, and habitat preferences are closely linked to sediment type and habitat complexity.</p>