Background: Infertility is a global public health problem among males, with asthenozoospermia representing the most common cause. Since flagellar activity is vital for proper fertilization, identification of the mechanisms controlling this process is crucial. Microtubules are necessary for sperm functionality; however, their regulatory proteins in humans require further research. DCDC2C belongs to the doublecortin domain-containing family and has a role in microtubule stabilization; therefore, DCDC2C could affect the sperm flagellar structure. Objectives: The goal of the present study was to examine the presence and possible relationship between DCDC2C expression and sperm motility in asthenozoospermia. Materials and Methods: This study involved sixty men from December 2024 to December 2025. The sperm samples were processed according to the WHO criteria (6th ed.). Conventional sperm characteristics, biochemical indicators of seminal plasma, DNA fragmentation, and chromatin condensation were evaluated. Immunofluorescence staining for DCDC2C was performed, especially with respect to flagellar localization. Results: DCDC2C-positive spermatozoa were significantly more common in the normozoospermic group (78.93 ± 1.67%) than in the asthenozoospermic group (17.27 ± 2.23%; p < 0.0001). No significant differences were found for seminal biochemical markers, sperm DNA fragmentation, or chromatin condensation. Discussion: Reduced detectable distal flagellar DCDC2C immunoreactivity was associated with asthenozoospermia. Conclusions: DCDC2C protein expression is highly correlated with sperm movement, indicating that DCDC2C is a potential molecular marker for the diagnosis of asthenozoospermia.