The research aims at constructing an instrument for measuring the selective visual attention of basic education students in Gaza, and verifying its validity and reliability. The research sample consisted of 200 grade ten students in Khan Younis (for the academic year, 2018 -2019). The evidence of constructive validity and the factorial validity of the instrument were investigated. Results of the predictive factorial analysis showed that the three tasks of the instrument covered a single potential factor namely selective visual attention. All slides of the selective visual attention tasks have achieved statistically significant correlations with the overall scores of the instrument. The content of the slides was also validated in relation to the instrument. The instrument reliability was also checked with the alpha coefficient for the final form of the instrument as a whole (0,962), and the split–half reliability coefficients ranged from (0.770 – 0.907). The final form of the instrument showed three major functions
