The study focused on determining the factors affecting the performance in essay type of test for Grade 11 students at Nasugbu Senior High School 1, Nasugbu, Batangas which would be the premise for a proposed modified action plan. The method used in choosing the sample was purposive sampling method. The data was acquired from fifty (50) grade 11 senior high school students during school year 2017-2018 and were evaluated in terms of frequency count, percentage, mean, and Pearson r. Based on the results, the research findings are: majority of the respondents belong to 15-17 age range and male gender comprised the majority; respondents agreed the test anxiety, sufficiency of linguistic proficiency, generation of ideas, structure/organization, and reading and writing practices and planning are factors affecting essay test performance. There was a very high significant relationship between test performance variable when correlated to factors affecting essay test performance, however no significant relationships were noted on age and gender variables. The proposed action plan was drawn by the researchers to develop the essay test performance of grade 11 senior high school students.