High-profile school attacks highlight the need for effective school safety solutions. School safety tip lines offer a prevention-based solution. However, little is known about their effectiveness. Using a quasi-experimental multilevel design, we examined the association between school tip-line adoption and violent threats and attacks at school (i.e., sexual assault, robbery, physical attacks with and without a weapon, firearm possession), including (1) the association between having a tip line and the rate and distribution of violent offense types, and (2) for schools with tip lines, whether strategies associated with tip-line implementation were associated with the rate and distribution of violent offense types. Using data from a nationally representative sample of 1,226 public middle and high schools, we conducted multivariable regression models using propensity score weights. Schools with tip lines did not have significantly lower rates of total offenses but were associated with an expected distributional difference: more violent threats and fewer violent attacks. Tip line implementation strategies were mixed. Recommendations for tip-line adoption and implementation are discussed.