Background Patient‐reported outcomes (PROs) are important measures of treatment response in heart failure. We assessed temporal trends in and factors associated with inclusion of PROs in heart failure randomized controlled trials (RCTs). Methods and Results We searched MEDLINE, Embase, and CINAHL for studies published between January 2000 and July 2020 in journals with an impact factor ≥10. We assessed temporal trends using the Jonckheere‐Terpstra test and conducted multivariable logistic regression to explore trial characteristics associated with PRO inclusion. We assessed the quality of PRO reporting using the Consolidated Standards of Reporting Trials (CONSORT) PRO extension. Of 417 RCTs included, PROs were reported in 226 (54.2%; 95% CI, 49.3%–59.1%), with increased reporting between 2000 and 2020 ( P <0.001). The odds of PRO inclusion were greater in RCTs that were published in recent years (adjusted odds ratio [aOR] per year, 1.08; 95% CI, 1.04–1.12; P <0.001), multicenter (aOR, 1.89; 95% CI, 1.03–3.46; P =0.040), medium‐sized (aOR, 2.35; 95% CI, 1.26–4.40; P =0.008), coordinated in Central and South America (aOR, 5.93; 95% CI, 1.14–30.97; P =0.035), and tested health service (aOR, 3.12; 95% CI, 1.49–6.55; P =0.003), device/surgical (aOR, 6.66; 95% CI, 3.15–14.05; P <0.001), or exercise (aOR, 4.66; 95% CI, 1.81–12.00; P =0.001) interventions. RCTs reported a median of 4 (interquartile interval , 3–6) of a possible of 11 CONSORT PRO items. Conclusions Just over half of all heart failure RCTs published in high impact factor journals between 2000 and 2020 included PROs, with increased inclusion of PROs over time. Trials that were large, tested pharmaceutical interventions, and coordinated in North America / Europe had lower adjusted odds of reporting PROs relative to other trials. The quality of PRO reporting was modest.