States of reduced self-control described as ego depletion have been shown to impair sport task performance. Recently, self-talk has emerged as a successful method to counteract ego depletion effects in cognitive tasks. Extending this line of research, the present study examined the effects of a self-talk intervention on attention functions and performance in a golf-putting task under conditions of ego depletion. Two studies were conducted; the first involved a simple putting task, whereas in the second, a divided attention factor was introduced in addition. Participants in the first experiment were 62 sport science students (30 females and 32 males, M_age = 18.58, SD = 1.03) who were randomly assigned into experimental (n = 31) and control (n = 31) groups. Participants in the second experiment were 54 sport science students (27 females and 27 males, M_age = 19.91, SD = 1.04) who were randomly assigned into experimental (n = 27) and control (n = 27) groups. Both experiments were completed in a single session that lasted approximately 60 min. All participants were tested individually. The procedures included (a) baseline performance assessment consisting of two sets of ten putts, (b) practice period, consisting of six sets of five putts, during which the experimental group was also introduced to the use of strategic self-talk, (c) an ego-depleting task, and (d) final performance assessment, which was identical to the baseline. The results showed that in both experiments, performance of the experimental group increased from baseline to final assessment (experiment 1, p < 0.001; experiment 2, p = 0.023), whereas that of the control group had no significant change (experiment 1: p = 0.241; experiment 2: p = 0.407). The findings showed that self-talk is an effective strategy for buffering the effects of ego depletion and suggest that improved attention functions are a viable mechanism for explaining the facilitating effects of self-talk on sport performance tasks.