Background: Phlebitis and pain are among intravenous injection's most common side effects. Different pharmacological and non-pharmacological techniques have been used to treat phlebitis. Aloe vera gel and warm compress are non-pharmacological nursing methods for phlebitis. Objectives: The present study compares the effect of Aloe vera and warm compress on pain due to phlebitis in children admitted to pediatric wards. Methods: This single-blind clinical trial study was conducted on 90 children with phlebitis. The participants were selected using convenience sampling and randomly assigned to three control, Aloe vera compress intervention, and warm compress intervention groups. The data in this study were collected using the patient demographic information questionnaire and Wong-Baker Faces Pain Rating Scale. The pain scores were evaluated in all three groups before the intervention. The intervention for the children in the warm compress group was a warm compress for 20 minutes twice daily (once every 12 hours). The intervention for the Aloe vera compress group was 5 cc of Aloe vera gel applied twice daily (once every 12 hours) for three days. Pain intensity was recorded and assessed in the pre-intervention stage for the children in all three groups. It was also measured for the warm compress group half an hour after the intervention and for the Aloe vera group at the beginning of the intervention. Pain intensity was also measured and evaluated for the children in the control group. Data analysis was performed with SPSS-22 software at a significance level of less than 0.05 (P < 0.05) using the chi-square test, independent samples t-test, one-way analysis of variance (ANOVA), and Fisher’s exact test. Results: The ANOVA results showed that there was no statistically significant difference between the three groups (P > 0.05) in the average pain intensity scores before the intervention and the first day after the intervention, but the average pain intensity scores in the three groups on the second day (P = 0.04) and the third day (P = 0.002) showed a statistically significant difference after the intervention. On the third day, the difference in the pain intensity scores was significant between the two intervention groups (P = 0.03) and the control group. Moreover, the pain intensity score for the children in the Aloe vera group decreased more significantly compared to the warm compress group (P = 0.001). Conclusions: The results showed that applying both Aloe vera and warm compresses effectively reduced the pain induced by phlebitis, but Aloe vera reduced the pain caused by phlebitis more than warm compress. Thus, the Aloe vera compress can be used as an easy and simple method to reduce the pain caused by phlebitis.