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PEOPLE GROUP PROFILE

The Big Sepik of Papua New Guinea

The Big Sepik of Papua New Guinea, numbering approximately 18,500 people, are No Longer Unreached. They are an indigenous ethnic group of Papua New Guinea They are an Indigenous people, in the New Guinea people cluster of the Pacific Islander Peoples affinity bloc. Their primary religion is Christianity - Roman Catholicism. They primarily speak Iatmul.

Photo by Google. (2025). Image generated by Gemini 2.5 Flash: Big Sepik

Fast Facts:

Affinity Group: Asian Pacific Rim Peoples
Country: Papua New Guinea
People Cluster: New Guinea
Primary Language(s): Iatmul (ian)
Primary Religion(s): Christianity - Roman Catholicism
Population: 18,500
Strategic Progress Index (SPI): No Longer Unreached
Global Status of Evangelical Christianity (GSEC): 5% or Greater but Less than 10% Evangelical
People Group ID: PG009782
View on Joshua Project

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Pray for the Big Sepik of Papua New Guinea

Join others around the world in praying for the lost to be saved, the gospel to advance, the global Church to grow, and for laborers to be sent out and sustained in the harvest.

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Dig Deeper (Religion):

Primary Religion: Christianity - Roman Catholicism
Religious Affiliation: Christianity

%
Christianity - Roman Cath… Adherents

Dig Deeper (Language):

Primary Language: Iatmul
Language Family: Ndu

%
Iatmul Speakers

Media Resources in Iatmul:

Films:

No entries found for: Iatmul(ian). Help build some!

Provided by the Jesus Film Project

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Bible Resources in Iatmul:

Provided by Faith Comes by Hearing

Or check out the Iatmul bible resources at Bible.com

Linked from YouVersion

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Next steps for the Big Sepik

The Big Sepik are Unengaged and Unreached, which means there are less than 2% evangelical Christian populations among which there are no known efforts focused on establishing self-sustaining churches consistent with evangelical faith and practice.

Begin signifcant prayer and fasting for this group
Send cross-cultural teams to discover and research this people group
Begin gospel seed sowing and church planting among this group

Next steps for the Big Sepik

The Big Sepik are Engaged yet Unreached, which means there are less than 2% evangelical Christian populations but there are sustained efforts at establishing self-sustaining churches consistent with evangelical faith and practice.

Continue prayer and fasting for this group
Continue gospel seed sowing and church planting among this group
Begin training up local leaders to lead and develop strategies to reach their own people

Next steps for the Big Sepik

The Big Sepik are No Longer Unreached, which means there are more than 2% evangelical Christian populations and there are churches consistent with evangelical faith and practice. There is still more to be done among them.

Empower local believers to begin praying for their own people
Continue gospel seed sowing and church planting among this group
Encourage local leaders to being leading church planting strategy and looking for Unreached and Unengaged groups nearby

Pray specifically for the Big Sepik of Papua New Guinea

"And you will know the truth, and the truth will set you free.”
readJohn 8:32

Pray for those who live enslaved to sin to hear and receive the truth of the gospel and be set free.

I saw in the night visions, and behold, with the clouds of heaven there came one like a son of man, and he came to the Ancient of Days and was presented before him. And to him was given dominion and glory and a kingdom, that all peoples, nations, and languages should serve him; his dominion is an everlasting dominion, which shall not pass away, and his kingdom one that shall not be destroyed.
readDaniel 7:13-14

Pray that the gospel will advance so that all peoples will come to know the Son of Man, who has been given dominion and glory and a kingdom, and that they will bow before Him and serve Him forever.

Turn, O LORD, deliver my life; save me for the sake of your steadfast love.
readPsalm 6:4

Pray that as people place their faith in Christ and still struggle with the worries of this life, God will deliver them from worry for the sake of His steadfast love.

For so the Lord has commanded us, saying, “‘I have made you a light for the Gentiles, that you may bring salvation to the ends of the earth.’”
readActs 13:47

Pray that as people come to faith, they will follow the Lord's leading to go to their neighbors and share the treasure they found in Christ.

Big Sepik (ROP3 - 101423) reported in the following countries:

To download a comprehensive people group list in spreadsheet form, visit our Research Data page.

Peoplegroups.org relies on updates from the field and other organizations for much of our data, so if you have any updates, please contact us. We use various international naming standards. For a list of these standards and fields, visit our Definitions page.

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