Importance: General practitioners (GPs) sometimes initiate a treatment despite not expecting it to improve patients' symptoms by any physiological mechanism. These essentially placebo treatments are ethically controversial, and their frequency is unclear. They involve risks for patients, but to estimate these, more data are needed. Objective: To develop a more precise overview of the rate at which GPs prescribe essentially placebo treatments. Design, Setting, and Participants: This cross-sectional survey study included currently practicing GPs from 20 European countries and Israel who responded to online questionnaires. The online questionnaires were taken between December 12, 2019, and August 4, 2021, and analyzed on April 28, 2022. Respondents were contacted by national representatives, either through personal networks (convenience sampling) or an existing database (volunteer sampling). Main Outcomes and Measures: The main outcome was the rate of essentially placebo prescriptions, given as the rate per week and the proportion of consultations. Secondary outcomes were the associations between this rate and GP background characteristics (gender, age, education about placebos, years of experience, patients seen, and working hours per week). Results: A total of 952 practicing GPs responded (453 of 745 [61%] female; mean [SD] age of 48.02 [11.95] years), and 669 answered all questions. Overall, 689 of 818 respondents (84%) indicated they had prescribed an essentially placebo treatment at least once. Overall, the median (IQR) rate of essentially placebo prescriptions was 0.5 (0.1 to 2.0) per week or 0.67% (0.06% to 2.50%) of consultations. The prescription rate was higher in men (β = 1.94 [95% CI, 0.58 to 3.29]; P = .005), those with more work experience (β = 0.12 [95% CI, 0.06 to 0.18]; P < .001), and those who work fewer hours per week (β = -0.08 [95% CI, -0.13 to -0.03]; P = .001). Conclusions and Relevance: In this survey study of GPs across 21 countries, essentially placebo prescriptions featured in a small minority of consultations, but they nevertheless occurred regularly for most GPs. Rates varied only slightly by GP background characteristics. This suggests that essentially placebo prescriptions were common at a population level, which poses risks for the patient-GP relationship and creates medical risks for patients. Future research should further investigate the decision-making process behind these prescriptions and their effects on patients.