The MSN-001A1 Delta Plus (aka δ Plus) is a variant of the MSN-001 Delta Gundam which appears in the novel and OVA Mobile Suit Gundam Unicorn. It is piloted by Riddhe Marcenas.

The Delta Plus is a prototype transformable mobile suit developed in U.C. 0090, which can serve as an all-purpose attack unit. It is based on the MSN-001 δ Gundam, a transformable mobile suit designed during the Gryps Conflict that, because of problems with insufficient frame strength, was completed as the non-transforming MSN-00100 Hyaku Shiki. While Anaheim Electronics was trying various approaches to develop a production model of the transformable Zeta series, it also simultaneously conducted a reinvestigation of the shelved Delta plan, creating the Delta Plus as a result. The Delta Plus' main feature is its capability to reenter the atmosphere unassisted thanks to its ability to transform into a waverider mode. It is also capable of atmospheric flight under the influence of 1G because of its high thrust output and is also equipped with a Bio-sensor. Due to the Delta Plus being a non-standard prototype, only a limited number of these units were produced.