The theoretically-driven inoculation strategy has increasingly become used to counter disinformation regarding pivotal societal issues such as COVID-19 and climate change. The current study examines its ability to cultivate psychological reactance toward unethical public relations attacks called astroturf, ultimately making the disinformation less persuasive. To do so, a between-subjects online experiment (N = 534) was conducted. Results show: 1) the use of inoculation messages outperforms the often-recommended paracrisis no response strategy, 2) combining inoculation with explicit details and autonomy support can elicit reactance toward disinformation, and 3) the use of this strategy can influence attitudes and future behavioral intentions to engage with the attacked organization. Guidance and implications for increasing the development of proactive PR messages within research and practice are discussed.