BACKGROUND: There were 23,854 suicides by firearms in 2017 in the US, accounting for 60% of all gun deaths. Studying firearm-related mortalities is vital for reducing preventable gun deaths. This study aims to determine the association between state-level presence of restrictive firearm laws and suicide rates with firearms. STUDY DESIGN: This ecological study used data from the CDC Wide-Ranging Online Data for Epidemiologic Research on decedents older than 18 years who died from intentional self-harm with firearms between 2009 and 2018. Exposures of interest were state-level restrictive firearm laws: background checks on private sales, mandatory waiting periods, and prohibited possession for domestic violence restraining orders or mental health red flags. Outcomes were rates of suicide with firearms per 100,000 persons over the 10-year period within each state. Welch’s t-tests compared mean mortality rates in exposed and unexposed states. RESULTS: There were 208,621 deaths from intentional self-harm with firearms from 2009 to 2018. States with background checks, mandatory waiting periods, and prohibited possession were associated with lower suicide rates for all firearm types compared with states without these laws (p < 0.05). Only states with background checks and mandatory waiting periods were associated with lower suicide rates by handguns and large firearms (p < 0.05). CONCLUSION: Background checks and mandatory waiting periods correlated with fewer suicides by all firearms and specific firearm types. This reduction could be due to firearm laws directly preventing people from accessing guns or existing concurrently with other suicide prevention measures. More research should be directed to understanding how firearm laws can help reduce suicide rates.