* "Banaag at Sikat" (1906) - This is considered his magnum opus and is a classic Filipino novel depicting the social issues of the time, particularly the struggle between the rich and the poor. It is a pioneering work in Tagalog literature and is still widely read today.
* "Ang Dalawang Mukha" (1909) - This novel is considered the first Filipino novel to focus on the lives of women and their struggles for equality. It explores themes of love, betrayal, and social injustice.
* "Pambansang Diksiyonaryo ng Wikang Pilipino" (1940) - This dictionary is a landmark work that standardized the Filipino language and is still the most authoritative reference work for Tagalog today.
* "Balarila ng Wikang Pambansa" (1940) - This grammar book, written with his wife, Paz Marquez Benitez, is a comprehensive guide to the Filipino language.
These are just a few of Lope K. Santos' many important works. His writings have had a profound impact on Filipino literature and the development of the Filipino language, making him a highly respected figure in Philippine history.