Background: The study aimed to assess the reliability, validity, and responsiveness of the Polish version of Knee Outcome Survey Activities of the Daily Living Scale (KOS-ADLS) in a group of patients after arthroscopic reconstruction of the anterior cruciate ligament (ACL). Methods: The study was a longitudinal study with repeated measures. One hundred and twelve subjects who qualified for arthroscopic ACL reconstruction (mean age = 31.8 years) were initially enrolled in this study. The Polish version of KOS-ADLS and Short Form-36 v. 2.0 (SF-36) were used. Results: The Polish version of KOS-ADLS in subjects after ACL rupture demonstrated excellent internal consistency (Cronbach’s alpha for KOS-ADLS- total = 0.91), and test–retest reliability using the intraclass correlation coefficient (ICC-total = 0.98). The standard error of measurement (SEM) value was 0.81 and the minimal detectable change (MDC) was 2.23 for KOS-ADLS-total. The validity analysis showed a moderate and low correlation between KOS-ADLS and different domains of SF-36 from r = 0.354 between KOS-ADLS activity and the physical component scale (PCS) of SF-36: to r = 0.206 between KOS-ADLS activity and the mental component scale (MCS) of SF-36. Conclusions: The Polish version of KOS-ADLS turned out to be a reliable, valid and responsive self-reported outcome measure, allowing for the self-assessment of symptoms and function related to the knee joint impairment after ACL reconstruction. Therefore, the scale can be applied in clinical practice and research.