Most previous studies on self–other discrepancies in decision making have mainly focused on risky decisions in finance, romantic relationships and medicine, paying less attention to intertemporal choices. Although several studies have recently begun to investigate self–other differences in intertemporal choices, the findings of these studies have been inconsistent. Some studies have reported that people prefer more sooner and smaller rewards when deciding for the self than for others, whereas others found that people prefer more later and larger rewards when deciding for the self than for others. Moreover, previous studies on self–other differences in intertemporal choices have mainly focused on decisions of gains. Given that people show different choice preferences for gains and losses, the present study aims to investigate self–other discrepancies in intertemporal choices in both gain and loss situations. A power analysis conducted in G*power (version 3.1.9.2) indicated that a minimum of the required total sample size was N = 37 to achieve a sufficient power (1-β = 0.80) with a medium effect size of f = 0.25. Forty-five undergraduate students were recruited to participate in the study. Two participants were excluded from the analyses because they doubted that the decisions for the other person were real on the post-experiment self-report questionnaire. Thus, the remaining 43 participants (25 females, Mage = 19.63 years, SDage = 1.33) were included in the analyses. A 2 (decision target: self or other) × 2 (decision situation: gain or loss) within-subjects design was conducted in this study. We adopted the intertemporal choice task developed by Huang et al. (2017), in which participants were asked to choose between an immediate and a delayed option for themselves or others. The immediate option was 10 RMB, and this amount was fixed in all choices. The delayed option was designed to combine different outcome magnitude and delay times. The outcome magnitude varied from 10.5 to 30 RMB in 12 steps, and the delay time was 7, 14 or 30 days. The formal experiment consisted of four blocks. Within each block, 72 trials were presented in a pseudo-random order. Each participant performed 288 total trials. At the beginning of each block, an instruction indicating decision target was presented for 5000 ms. Each trial began with a fixation cross varying randomly from 600 to 800 ms. Subsequently, an immediate option and a delayed option were presented simultaneously on the screen. Participants were required to press the key “F” when they choose the option displayed on the left side of the screen, or to press the key “J” when they choose the option displayed on the right side of the screen. The alternatives remained on the screen until the participants made a choice. Following their responses, each trial ended with a blank screen with presentation durations varying from 800 to 1000 ms. The results revealed that the main effect of decision target was significant, and the proportion of times that the participants chose the immediate option was significantly higher when making decisions for the self than for others. A significant main effect of decision situation was also observed, with participants choosing more immediate options in loss situations than in gain situations. The interaction between decision target and decision situation was also significant. Follow-up simple effect analysis revealed that the difference in proportion that the participants chose the immediate option between decisions for the self and those for others was nonsignificant in gain situations. However, participants chose more immediate options for themselves than for others in loss situations. To sum up, the present study provides the first evidence that gain–loss situation modulates self–other discrepancies in intertemporal choices. Our findings not only contribute to clarify the controversial results in the existing research, but also to intensify the understanding of the interactions between human economic decision-making and advanced social decision-making, and thus providing the scientific evidence for optimizing individual judgment and decision making.