Pepper exhibits genetic diversity and versatility in use. Knowledge of the genetic control of traits in peppers is of great importance to breeding programs given the variety of types, sizes, colors and flavors. The aim of the present study was to examine the inheritance of seedling and plant traits in ornamental pepper (Capsicum annuum). The experiment was conducted in a greenhouse in the plant biotechnology section of the Agricultural Sciences Center, Federal University of Paraíba. Seven ornamental pepper accessions (Capsicum annuum L.) belonging to CCA-UFPB's Germplasm Bank were used: UFPB001, UFPB004, UFPB77.3, UFPB099, UFPB134, UFPB137 and UFPB390. Morphoagronomic characterization was performed based on Capsicum descriptors (IPGRI, 1995), and twelve quantitative traits were evaluated regarding seedling and plant. The data were previously subjected to variance analysis and subsequent diallel analysis performed according to Hayman's (1954) method. The t statistic was used to test the adequacy of the additive-dominance model. Seedling height, hypocotyl diameter, cotyledon leaf length, plant height, first fork height, leaf length and width and chlorophyll a and b represent traits that conformed to the additive-dominant model. Genetic gains in regard to plant traits (plant height, first fork height, crown diameter and leaf length and width) in ornamental peppers are possible using breeding programs. Partial dominance of all plant traits is noted, and overdominance of the traits seedling height and cotyledon leaf length and width were observed. The parents UFPB001 and UFPB134 exhibited the highest concentration of favorable alleles for size traits and are indicated for selection for continued improvement programs.