Semantic similarity between stimuli can lead to false memories and can also potentially cause retroactive interference (RI) for veridical memories. Here, participants first learned spatial locations for "critical" words that reliably produce false memories in the Deese-Roediger-McDermott paradigm. Next, participants centrally viewed words that were semantically associated with half of the critical words. Finally, participants retrieved the spatial locations for the critical words. We found that spatial memory was worse for critical words whose semantic associates were shown versus not shown, suggesting that semantic relatedness caused RI. This effect occurred in three experiments when the interfering information was presented shortly before the spatial test but not when there was a 1-hour delay before the test, nor when the order of the spatial learning and associate learning phases were reversed. These findings suggest that RI can occur solely via semantic associates when all relevant responses and no distracting responses were available at retrieval. We consider these findings to be an example of cue overload, whereby cues can be overloaded indirectly via semantic associates, and to support the importance of both semantic similarity and temporal context in RI.