St Just in Roseland (Cornish: Lannsiek) is a village and civil parish in Cornwall, England, United Kingdom. The village is 6 miles (10 km) south of Truro and 2 miles (3 km) north of St Mawes, a small village within the parish of St Just in Roseland. The 2011 Census recorded the parish population as 1,158.

St Just in Roseland lies within the Cornwall Area of Outstanding Natural Beauty (AONB).

St Just in Roseland is noted for its 13th-century Church of England parish church, St Just’s Church, St Just in Roseland, set in riverside gardens planted with semitropical shrubs and trees, many of which are species rare in England. The church is on the edge of a tidal creek beside the Carrick Roads on the Fal Estuary just outside the main village. The path from the road to the church is lined with granite blocks carved with quotations and verses taken from the Bible.

The ornithologist Edward Hearle Rodd was born here. The lichenologist Peter Wilfred James (1930 - 2014) was born here although brought up in Sutton Coldfield. The cricketer Michael Harris (known as "Pasty" Harris) also came from the parish.

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  View from above the church looking across to St Just Creek
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  View from creek (low tide)
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  Lord's Prayer (1693)
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  Celtic cross

• "Online Catalogue for St Just in Roseland". Cornwall Record Office.

50°10′56.36″N 5°00′53.99″W / 50.1823222°N 5.0149972°W / 50.1823222; -5.0149972