Agility is unquestionably an important ability for tennis players, but there is an evident lack of studies focussing on the applicability of tennis-specific agility tests that capture a combination of the physical and cognitive agility performance. Therefore, the main aim of this study has been to design and test measurement properties of the tennis-specific reactive agility test, which would be feasible and practical for being regularly implemented and which would contain all the “ingredients” necessary for the test to be considered as a reactive agility sport-specific test. A total of 32 tennis youth tennis players (21 males and 11 females; 10,85 ± 1.50 years) participated in this study having at least three years playing experience, and regularly training at least 4 times per week. The measurement characteristics of the newly designed Reactive Agility Tennis-Specific (TSRAN) test have been established by comparing it with the two validated generic agility tests (MDA “ABCD” and STSLA) and with the two newly designed tennis-specific preplanned agility tests (TS-STSLA and TS- MDA). The new TS-RAN test overall reliability can be considered only as “moderate to good” (IntraClass Correlation coefficient: 0.74) although the results of participants showed really good internal consistency (Cronbach Alpha: 0.90), but the within subject reliability of the test proved to be unsatisfactory, as the participants showed to lack performance consistency. However, as that was the case with the whole test battery, that can be contributed to the sample of the participants, as the shown lack of performance consistency is not unexpected considering the very young age of participants who performed the test for the very first time. The new TS-RAN test was highly projected (0.91) on the same single latent dimension (extracted on the basis of the Guttman-Kaiser criterion), which variance can predominately be explained with the tennis-specific agility tests. The test’s greateststrength isits feasibility, which is really high since the test does not require any special set-up nor technical equipment, what makes it practical for being regularly implemented in practical setting. Further research are needed to confirm if the test will prove to have potential to be widely accepted and used.