Despite the rapidly increasing rate of non-suicidal self-injury (NSSI) among adolescents, there is a dearth of culturally appropriate psychological measures screening for NSSI among the adolescents in the Asian countries. This study aimed to develop and validate the Self-Harm Screening Inventory (SHSI), a culturally sensitive and suitable scale for screening adolescents for NSSI. In total, 514 Korean adolescents (aged 12-16 years) were recruited nationwide. All participants gave informed consent and completed the online self-report measures on NSSI, depression, anxiety, and self-esteem. Thereafter, preliminary items were developed through a series of steps: literature review, ratings of experts on self-harm and suicide, and statistical analyses. Ten of the 20 preliminary items were eliminated after exploratory factor analysis due to low endorsement and factor loading (less than .70). The final version of the SHSI comprised 10 binary items relating to self-harm behaviors within the past year (e.g., cut my body with sharp objects, hit my body). A confirmatory factor analysis supported a one-factor structure, as hypothesized. The one-factor model had a good model fit (x2(35) = 84.958, p < .001, RMSEA = .053, CFI = .981, TLI = .975, SRMR = .124). The SHSI also had good internal consistency (Cronbach's alpha = .795) and 4-week test-retest reliability (r = .786, p < .01). The SHSI had high correlations with another self-harm related scale, the Self-Harm Inventory (r = .773, p < .01), and moderate correlations with the Child Depression Inventory (r = .484, p < .01) and Revised Children's Manifest Anxiety Scale (r = .433, p < .01). Additionally, the SHSI was negatively correlated with the Rosenberg Self-Esteem Scale (r = -.399, p < .01). The findings indicate that the SHSI is a reliable and valid measure for the screening of self-harm behaviors among adolescents.