Under the contract, ABB will offer onshore power conversion and grid connection systems to feed the electricity into the local distribution grid.
The contract requires ABB to design, engineer, supply and commission the power conversion, switchgear and transformer solution as well as associated civil engineering and cabling works.
ABB will deliver transformers, medium voltage switchgear and power converters required for the project.
Phase one of the MeyGen development has the potential to generate about 86MW of electricity, enough to meet the energy needs of about 42,000 homes.
MeyGen expects to deploy about 398MW of offshore tidal stream turbines in the Pentland Firth over the next 10 years to deliver clean and renewable electricity to the UK National Grid.
Atlantis Resources chief executive officer Tim Cornelius said: "Forming partnerships with the leading players in the energy sector is key to delivering commercial-scale tidal power projects that allow us to harness the untapped potential of global tidal resources.
"ABB has clearly demonstrated exceptional expertise in this area and we are confident they will deliver the highest quality results. We look forward to working with the team at ABB to ensure the success of the MeyGen project."
ABB said the MeyGen tidal stream project will harvest the tidal resources of one of the most energetic maritime sites in Europe, the strait linking the Atlantic Ocean to the North Sea between the Orkney Islands and the Scottish mainland.
The initial 6MW demonstration phase of the tidal array scheme includes the installation of four submerged turbines in the Inner Pentland Firth, just north of Caithness.