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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 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): 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

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Dig Deeper (Religion):

Primary Religion: Roman Catholicism
Religious Affiliation: Christianity

%
Roman Catholicism 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

For the LORD knows the way of the righteous, but the way of the wicked will perish.
readPsalm 1:6

As many look for hope in worldly pleasures, pray they will hear and accept salvation through Christ, turn from destruction, and experience joy in the way of righteousness.

Children, obey your parents in the Lord, for this is right. “Honor your father and mother” (this is the first commandment with a promise).
readEphesians 6:1-2

Pray that God will bring young men and women to faith in Jesus and that the fruit of their faith will be a powerful testimony as they honor their parents.

Know that the Lord, he is God! It is he who made us, and we are his; we are his people, and the sheep of his pasture. Enter his gates with thanksgiving, and his courts with praise! Give thanks to him; bless his name!
readPsalm 100:3-4

Pray that as people place their faith in Christ, they will be in awe of the Lord God, their Creator, and will give Him thanksgiving and praise.

But when one turns to the Lord, the veil is removed.
read2 Corinthians 3:16

Give thanks to God for believers around the world who are willing to cross cultures to share the gospel with those who are perishing. Pray that He will work through their witness to draw many to turn to Him.

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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