In summary, our evaluation found that the ACT Pill Testing Trial was implemented as planned, that the service was well received by patrons and stakeholders, and that the service impacted positively on patron knowledge, attitudes and behaviours. The 2019 Groovin the Moo festival Pill Testing Trial, implemented by Pill Testing Australia, was the second government-sanctioned trial of its type in Australia. It was designed and implemented collaboratively between the key stakeholders, primarily Pill Testing Australia, Cattleyard Promotions, and key ACT Government agencies ACT Health and ACT Policing. Enough lead time was available to develop the trial carefully, with the result that it was implemented as planned and produced the types of outputs that the key stakeholders expected to see. The service provided harm reduction information to 234 patrons and identified seven substances containing a potentially dangerous substance, N-ethyl pentylone. The experience of testing and the accompanying harm reduction brief interventions produced a number of positive results in terms of participants’ self-reported drug harm reduction knowledge, their trust of health providers and other written sources of harm reduction information, and stated behavioural intentions regarding drug use.