On July 28, 2016, Grudem published an opinion piece on Townhall called "Why Voting for Donald Trump Is a Morally Good Choice". On October 9, the piece was retracted and replaced with one entitled "Trump's Moral Character and the Election". On October 19, the original piece was reinstated and another piece was published, entitled "If You Don't Like Either Candidate, Then Vote for Trump's Policies". Grudem endorsed Trump for re-election in 2020.
In his theological method, Grudem aims to compile what the entire Bible says about any given topic. He applied this approach in his Systematic Theology and has now done so more recently in Christian Ethics. Grudem describes the task of assembling verses and passages from the Bible on the analogy of a "jigsaw puzzle." This manner of deploying scripture has been criticized. Carl Braaten, an ecumenical Lutheran, argues that Grudem "piles up biblical proof-texts in blithe indifference to critical scholarship"; his "method is captive to the fundamentalist notion that the canon of biblical texts and their interpretation can be detached from the community that determined canonicity in the first place."
Grudem and Bruce A. Ware were at the center of Trinitarian debate in 2016 that began online and culminated in print publications. Both Grudem and Ware subscribe to a view of the Trinity called "eternal relations of submission and authority" or "eternal functional subordination" which claims that the Son is eternally submissive to the Father. Their view was challenged by prominent scholars as a deviation from the traditional view, that the Son only submits to the Father in the incarnation according to his human nature.
All of Grudem's research on gender-related issues is now contained in his major reference work Evangelical Feminism and Biblical Truth: an Analysis of over 100 Disputed Questions (Multnomah, 2004; Crossway, 2012).
Grudem's view of gender claims that men and women are equal in nature and dignity but operate within a hierarchy in which the husband is the head of the wife.
——— (2003). Business for the Glory of God: The Bible's Teaching on the Moral Goodness of Business. Wheaton, IL: Crossway Books. ISBN978-1-58134517-9. OCLC53131744.
——— (2004). Evangelical Feminism and Biblical Truth: an analysis of more than one hundred disputed questions. Sisters, OR: Multnomah Publishers. ISBN978-1-57673840-5. OCLC54897906.. Second edition Crossway, 2012.
——— (2016). "Free Grace" Theology: 5 Ways It Diminishes the Gospel. Wheaton, IL: Crossway Books. ISBN978-1-4335-5114-7.
———; Piper, John (2016). Fifty Crucial Questions: An Overview of Central Concerns About Manhood and Womanhood. Wheaton, IL: Crossway Books. ISBN978-1-43355184-0.
———; Moreland, J.P.; Meyer, Stepen C.; Shaw, Christopher; Gauger, Ann K. (2017). Theistic Evolution: A Scientific, Philosophical, and Theological Critique. Wheaton, IL: Crossway Books. ISBN978-1-43355286-1.
——— (2018). Christian Ethics: An Introduction to Biblical Moral Reasoning. Wheaton, IL: Crossway Books. ISBN978-1-43354965-6.
——— (1985). "Does kephal? ('head') mean 'source' or 'authority over' in Greek literature? - a survey of 2,336 examples". In George W. Knight III (ed.). The Role Relationship of Men and Women: New Testament teaching. Chicago, IL: Moody Press. ISBN9780802473691. OCLC11785448.