MS Project do not provide a tool to highlight a time period in Gantt chart.

So how can we do it?

First you create a new calendar. For example “Gantt Shade”

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In Exception tab, add the Time period you want to highlight. (From January to March)

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Right click on Gantt chart and select Nonworking Time…

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In Non-working time tab, in Calendar select Gantt Shade, in Draw select Behind task bars, in Color select Gray color.

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Now Time period from Jan to Mar has been highlighted.

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