Purpose: Derivational morphology and compounds are important aspects of academic vocabulary. However, investigation of the development of expressive derivational and compound morphology using language sampling is sparse. This cross-sectional study used three types of language samples to investigate quantitative and qualitative changes in the spontaneous production of derived words and compounds in early and late elementary-age children as a function of age and discourse type. Method: Twenty-three children in two age groups (early elementary, n = 12; late elementary, n = 11) participated. Three types of language samples were elicited: conversational (10-min conversation with an adult examiner), narrative ("I tell-you tell" narrative with single picture stimulus combined with a story stem narrative), and expository (explanation of how to play a favorite game or sport with text-based topic prompts). Language samples were transcribed using Systematic Analysis of Language Transcripts (Miller & Chapman, 2012) conventions with the addition of researcher-created codes to identify derived words and compounds. Quantitative measures (number of derived words, different derived words, number of compounds, and different compounds) were calculated as percentages of total words or number of different words to control for differing sample length. The types of derivational morphemes and compounds produced by children in each age group were listed and qualitatively analyzed for evidence of a sequential development of specific morpheme types, variation in complexity, and productivity. Results: Developmental change in quantitative and qualitative measures of derivational and compound morphology was evident across early and late elementary-age children in the language samples. Lists of derived words and compounds produced provided a rich source for analyzing developmental patterns in expressive morphology. Conversational and, to a lesser extent, expository discourse generated the greatest number and diversity of multimorphemic words. Conclusions: This research provided new insights into academic vocabulary development in elementary school-age children. The clinical usefulness of language sampling to quantitatively and qualitatively assess derivational morphology and compounds was demonstrated.