How nature of scientific knowledge (NOSK) or nature of science (NOS) and scientific inquiry (SI) are contextualized, or related to each other, significantly impacts both curriculum and classroom practice, specifically with respect to the teaching and learning of NOSK. NOS and NOSK are considered synonymous here, with NOSK more accurately conveying the meaning of the construct. Three US-based science education reform documents are used to illustrate the aforementioned impact. The USA has had three major reform documents released over a period of 20 years. The "Benchmarks for Science Literacy" was the first in 1993, followed by the "National Science Education Standards" (NSES) in 1996, and the newest, the "Next Generation Science Standards" (NGSS), was released in 2013. NOS or NOSK was strongly emphasized and given a prominent position in the first two, while the NGSS has marginalized the construct. It is categorized as a set of connections (with no specific standards or performance expectations) that can be made to some of the "Science Practices or Crosscutting Ideas." However, a careful conceptual analysis of how the NGSS positions NOSK/NOS relative to the previous reform documents reveals a complex situation related to how NOSK/NOS is contextualized and apparent assumptions about how NOSK/NOS is best taught and learned. A historical review of how NOSK/NOS is contextualized reveals a longstanding confusion concerning the relationship between NOSK/NOS and SI as well as about how the reform documents seem to assume how it can be best taught to students. The assumptions often run contrary to the empirical research on the teaching and learning of NOSK as well as call into question the ability of the NGSS to promote the perennial science education goal of scientific literacy.