Gypseous soil is collapsible soil, it is widespread in arid and semi-arid areas of low rainfall intensity as a result of water evaporation. Gypseous soil is commonly formed in an unsaturated state with low dry density and moisture content. Naturally, gypseous soil can be found with a wide range of gypsum contents. Gypsum is a mineral rock formed by calcium sulfate dihydrate, (CaSO4.2H2O). The presence study investigates the compressibility and collapsibility characteristics of gypsified sandy soil. The pure gypsum is mixed carefully in dry conditions with the pure sandy soil as weight percentages. Series of laboratory Oedometer tests such as consolidation and single Oedometer collapse tests are carried out on gypsum-sand mixture with gypsum percentages of 0, 10, 20, 40, 60, 80, and 100%. The test results show that the coefficient of compressibility increased sharply up to a gypsum content of 40% and then decreased. While the coefficient of rebound remains almost constant and ranges between (0.01–0.02) for all gypsum contents. The coefficient of consolidation is difficult to calculate because the 50% consolidation point wasn’t clear on settlement-time curve. The gypsified soil samples with gypsum content above 40% exhibit collapsible behavior, the samples susceptible to significant volume reduction or settlement where their voids are compressed upon inundation. Below the gypsum content of 40%, negligible collapse deformation is observed. The collapse potential is proportionally increased with the increase of gypsum content and inundation time. The higher gypsum content generally leads to significant reduction in void ratio and settlement potential. Compacted gypsified samples can exhibit collapse deformation depending on the gypsum content, compaction effort, initial water content, collapse vertical stress and wetting interval.