This chapter discusses the issues researchers must consider when selecting target words in texts provided to research participants in incidental vocabulary acquisition studies. It contends that they must ensure that the words are appropriate in terms of frequency, difficulty, context, and relevance to the participants’ existing knowledge and learning goals, as these aspects may affect the validity and reliability of the study outcomes. After introducing the topics covered in the chapter, the pros and cons of using real, nonce, and foreign word targets are expounded. Next, questions arising from the use of multiword units instead of single orthographic words are addressed. Then, several target-word properties are considered, including cognateness, lexicalization, congruency, phonology and orthography, word class, concreteness or imageability, polysemy, word length, frequency, range, and dispersion. Subsequently, examples of how corpus tools can assist researchers in balancing target words in terms of their properties and the execution of other textual analyses are provided. Finally, concluding remarks on target-word selection issues are presented.