diff --git a/PiHoleShell/PiHoleShell.psm1 b/PiHoleShell/PiHoleShell.psm1
index 50f5085..a28485d 100644
--- a/PiHoleShell/PiHoleShell.psm1
+++ b/PiHoleShell/PiHoleShell.psm1
@@ -31,7 +31,7 @@ Export-ModuleMember -Function @(
         'Get-PiHoleStatsRecentBlocked', 'Get-PiHoleStatsQueryType', 'Get-PiHoleStatsTopDomain', 'Get-PiHoleStatsSummary', 'Get-PiHoleStatsTopClient', 'Get-PiHoleStatsQuerySuggestions', `
         'Get-PiHoleStatsUpstream', 'Get-PiHoleStatsDatabaseUpstream', 'Get-PiHoleStatsDatabaseSummary', 'Get-PiHoleStatsDatabaseTopDomain', 'Get-PiHoleStatsDatabaseTopClient', 'Get-PiHoleStatsDatabaseQueryType' `
         #ListManagement
-        'Get-PiHoleList', 'Search-PiHoleListDomain', 'Add-PiHoleList', 'Remove-PiHoleList', `
+        'Get-PiHoleList', 'Search-PiHoleListDomain', 'Add-PiHoleList', 'Remove-PiHoleList', 'Update-PiHoleList', `
         #FTLInformation
         'Get-PiHoleInfoMessage', 'Get-PiHoleInfoHost', 'Get-PiHoleInfoClient', 'Get-PiHoleInfoLogin', 'Get-PiHoleInfoSystem', 'Get-PiHoleInfoFtl', `
         'Get-PiHoleInfoSensors', 'Get-PiHoleInfoDatabase', 'Get-PiHoleInfoVersion', 'Get-PiHoleInfoMetrics', 'Get-PiHoleInfoMessageCount', 'Remove-PiHoleInfoMessage', `
diff --git a/PiHoleShell/Public/ListManagement/Update-PiHoleList.ps1 b/PiHoleShell/Public/ListManagement/Update-PiHoleList.ps1
new file mode 100644
index 0000000..d6789fe
--- /dev/null
+++ b/PiHoleShell/Public/ListManagement/Update-PiHoleList.ps1
@@ -0,0 +1,152 @@
+function Update-PiHoleList {
+    <#
+.SYNOPSIS
+Update a list
+
+.DESCRIPTION
+Updates an existing list's Comment, Group(s), and/or Enabled state. The underlying Pi-hole API
+replaces the entire list on update, so any property you don't pass here is preserved by first
+reading the list's current value and resending it - nothing is silently cleared just because
+you only meant to change one property.
+
+.PARAMETER PiHoleServer
+The URL to the PiHole Server, for example "http://pihole.domain.com:8080", or "http://192.168.1.100"
+
+.PARAMETER Password
+The API Password you generated from your PiHole server
+
+.PARAMETER Address
+The URL of the list to update
+
+.PARAMETER Type
+Whether this is an Allow list or a Block list
+
+.PARAMETER Comment
+The new comment for the list. Leave unset to keep the list's current comment
+
+.PARAMETER Group
+The group(s) this list should apply to. Leave unset to keep the list's current group(s)
+
+.PARAMETER Enabled
+Whether the list should be enabled. Leave unset to keep the list's current state
+
+.PARAMETER IgnoreSsl
+Set to $true to skip SSL certificate validation
+
+.PARAMETER RawOutput
+This will dump the response instead of the formatted object
+
+.EXAMPLE
+Update-PiHoleList -PiHoleServer "http://pihole.domain.com:8080" -Password "your-app-password" -Address "https://hosts-file.net/ad_servers.txt" -Type Block -Enabled $false
+    #>
+    [CmdletBinding(HelpUri = 'https://ftl.pi-hole.net/master/docs/#put-/lists/-list-')]
+    [Diagnostics.CodeAnalysis.SuppressMessage("PSUseShouldProcessForStateChangingFunctions", "", Justification = "Ignoring for now")]
+    [System.Diagnostics.CodeAnalysis.SuppressMessageAttribute("PSAvoidUsingPlainTextForPassword", "Password")]
+    param (
+        [Parameter(Mandatory = $true)]
+        [System.URI]$PiHoleServer,
+        [Parameter(Mandatory = $true)]
+        [string]$Password,
+        [Parameter(Mandatory = $true)]
+        [System.Uri]$Address,
+        [Parameter(Mandatory = $true)]
+        [ValidateSet("Allow", "Block")]
+        [string]$Type,
+        [string]$Comment,
+        [string[]]$Group,
+        [Nullable[bool]]$Enabled,
+        [bool]$IgnoreSsl = $false,
+        [bool]$RawOutput = $false
+    )
+
+    try {
+        if (-not $PSBoundParameters.ContainsKey('Comment') -and -not $PSBoundParameters.ContainsKey('Group') -and -not $PSBoundParameters.ContainsKey('Enabled')) {
+            throw "To update $Address, you must specify the Comment, Group, and/or Enabled parameter"
+        }
+
+        $ExistingList = Get-PiHoleList -PiHoleServer $PiHoleServer -Password $Password -IgnoreSsl $IgnoreSsl -List $Address | Where-Object { $_.Type -eq $Type }
+
+        if (-not $ExistingList) {
+            throw "Cannot find $Address of type $Type on $PiHoleServer! Please use Add-PiHoleList to create it"
+        }
+
+        $AllGroups = Get-PiHoleGroup -PiHoleServer $PiHoleServer -Password $Password -IgnoreSsl $IgnoreSsl
+
+        $GroupNamesToResolve = if ($PSBoundParameters.ContainsKey('Group')) { $Group } else { $ExistingList.Groups }
+
+        $AllGroupsNames = @()
+        $AllGroupsIds = @()
+        foreach ($GroupItem in $GroupNamesToResolve) {
+            $FoundGroup = $AllGroups | Where-Object { $_.Name -eq $GroupItem }
+            if ($FoundGroup) {
+                $AllGroupsNames += $FoundGroup.Name
+                $AllGroupsIds += $FoundGroup.Id
+            }
+            else {
+                throw "Cannot find $GroupItem on $PiHoleServer! Please use Get-PiHoleGroup to list all groups"
+            }
+        }
+
+        $Sid = Request-PiHoleAuth -PiHoleServer $PiHoleServer -Password $Password -IgnoreSsl $IgnoreSsl
+
+        # The API replaces the whole list on update, so any property not explicitly passed here
+        # is resent using the list's current value to avoid silently clearing it.
+        $Body = @{
+            comment = if ($PSBoundParameters.ContainsKey('Comment')) { $Comment } else { $ExistingList.Comment }
+            groups  = [Object[]]($AllGroupsIds)
+            enabled = if ($PSBoundParameters.ContainsKey('Enabled')) { $Enabled } else { $ExistingList.Enabled }
+        }
+
+        $Params = @{
+            Headers              = @{sid = $($Sid) }
+            Uri                  = "$($PiHoleServer.OriginalString)/api/lists/$Address`?type=$($Type.ToLower())"
+            Method               = "Put"
+            SkipCertificateCheck = $IgnoreSsl
+            Body                 = $Body | ConvertTo-Json -Depth 10
+            ContentType          = "application/json"
+        }
+
+        $Response = Invoke-RestMethod @Params
+
+        if ($RawOutput) {
+            Write-Output $Response
+        }
+        else {
+            $ObjectFinal = foreach ($Item in $Response.lists) {
+                if ($Item.date_updated -eq 0) {
+                    $DateUpdated = $null
+                }
+                else {
+                    $DateUpdated = (Convert-PiHoleUnixTimeToLocalTime -UnixTime $Item.date_modified).LocalTime
+                }
+
+                [PSCustomObject]@{
+                    Address        = $Item.address
+                    Comment        = $Item.comment
+                    Groups         = $AllGroupsNames
+                    Enabled        = $Item.enabled
+                    Id             = $Item.id
+                    DateAdded      = (Convert-PiHoleUnixTimeToLocalTime -UnixTime $Item.date_added).LocalTime
+                    DateModified   = (Convert-PiHoleUnixTimeToLocalTime -UnixTime $Item.date_modified).LocalTime
+                    Type           = $Item.type.SubString(0, 1).ToUpper() + $Item.type.SubString(1).ToLower()
+                    DateUpdated    = $DateUpdated
+                    Number         = $Item.number
+                    InvalidDomains = $Item.invalid_domains
+                    AbpEntries     = $Item.abp_entries
+                    Status         = $Item.status
+                }
+            }
+            Write-Output $ObjectFinal
+        }
+    }
+
+    catch {
+        Write-Error -Message $_.Exception.Message
+    }
+
+    finally {
+        if ($Sid) {
+            Remove-PiHoleCurrentAuthSession -PiHoleServer $PiHoleServer -Sid $Sid -IgnoreSsl $IgnoreSsl
+        }
+    }
+}
diff --git a/README.md b/README.md
index 5cce8e3..b4711ea 100644
--- a/README.md
+++ b/README.md
@@ -116,6 +116,7 @@ Functions marked 🚧 are still under active development — signatures and outp
 | `Get-PiHoleList` 🚧 | Get lists |
 | `Remove-PiHoleList` | Remove a list |
 | `Search-PiHoleListDomain` | _No description yet_ |
+| `Update-PiHoleList` | Update a list |
 
 ### Metrics
 
diff --git a/tests/ListManagement/Update-PiHoleList.Integration.Tests.ps1 b/tests/ListManagement/Update-PiHoleList.Integration.Tests.ps1
new file mode 100644
index 0000000..61d73bd
--- /dev/null
+++ b/tests/ListManagement/Update-PiHoleList.Integration.Tests.ps1
@@ -0,0 +1,94 @@
+# Requires -Module Pester
+#
+# Integration tests that call a REAL Pi-hole server. Configure tests/IntegrationConfig.local.ps1
+# (copy it from IntegrationConfig.example.ps1) before running. Tests are skipped automatically
+# if that file is missing.
+
+$script:ConfigAvailable = Test-Path (Join-Path (Split-Path $PSScriptRoot -Parent) 'IntegrationConfig.local.ps1')
+
+Describe 'Update-PiHoleList (Integration)' -Tag 'Integration' {
+    BeforeAll {
+        Import-Module .\PiHoleShell\PiHoleShell.psm1 -Force
+
+        $script:TestListAddress = 'https://blocklistproject.github.io/Lists/alt-version/ransomware-nl.txt'
+
+        $configPath = Join-Path (Split-Path $PSScriptRoot -Parent) 'IntegrationConfig.local.ps1'
+        if (Test-Path $configPath) {
+            . $configPath
+            $script:PiHoleServer = $PiHoleServer
+            $script:PiHoleToken = $PiHoleToken
+            $script:PiHoleIgnoreSsl = $PiHoleIgnoreSsl
+
+            # Defensive cleanup in case a previous failed run left the test list behind
+            Remove-PiHoleList -PiHoleServer $script:PiHoleServer -Password $script:PiHoleToken -IgnoreSsl $script:PiHoleIgnoreSsl -Address $script:TestListAddress -Type Block -Confirm:$false -ErrorAction SilentlyContinue | Out-Null
+        }
+    }
+
+    AfterAll {
+        if ($script:PiHoleServer) {
+            Remove-PiHoleList -PiHoleServer $script:PiHoleServer -Password $script:PiHoleToken -IgnoreSsl $script:PiHoleIgnoreSsl -Address $script:TestListAddress -Type Block -Confirm:$false -ErrorAction SilentlyContinue | Out-Null
+        }
+    }
+
+    It 'updates only the comment, preserving Enabled and Group' -Skip:(-not $script:ConfigAvailable) {
+        Add-PiHoleList -PiHoleServer $script:PiHoleServer -Password $script:PiHoleToken -IgnoreSsl $script:PiHoleIgnoreSsl -Address $script:TestListAddress -Type Block -Comment 'original comment' -Enabled $true | Out-Null
+
+        $result = Update-PiHoleList -PiHoleServer $script:PiHoleServer -Password $script:PiHoleToken -IgnoreSsl $script:PiHoleIgnoreSsl -Address $script:TestListAddress -Type Block -Comment 'updated comment'
+        $result | Format-List | Out-String | Write-Host
+
+        $result | Should -Not -BeNullOrEmpty
+        $result.Comment | Should -Be 'updated comment'
+        $result.Enabled | Should -BeTrue
+        $result.Groups | Should -Contain 'Default'
+
+        Remove-PiHoleList -PiHoleServer $script:PiHoleServer -Password $script:PiHoleToken -IgnoreSsl $script:PiHoleIgnoreSsl -Address $script:TestListAddress -Type Block -Confirm:$false | Out-Null
+    }
+
+    It 'updates only Enabled, preserving the current comment' -Skip:(-not $script:ConfigAvailable) {
+        Add-PiHoleList -PiHoleServer $script:PiHoleServer -Password $script:PiHoleToken -IgnoreSsl $script:PiHoleIgnoreSsl -Address $script:TestListAddress -Type Block -Comment 'keep this comment' -Enabled $true | Out-Null
+
+        $result = Update-PiHoleList -PiHoleServer $script:PiHoleServer -Password $script:PiHoleToken -IgnoreSsl $script:PiHoleIgnoreSsl -Address $script:TestListAddress -Type Block -Enabled $false
+        $result | Format-List | Out-String | Write-Host
+
+        $result | Should -Not -BeNullOrEmpty
+        $result.Comment | Should -Be 'keep this comment'
+        $result.Enabled | Should -BeFalse
+
+        Remove-PiHoleList -PiHoleServer $script:PiHoleServer -Password $script:PiHoleToken -IgnoreSsl $script:PiHoleIgnoreSsl -Address $script:TestListAddress -Type Block -Confirm:$false | Out-Null
+    }
+
+    It 'returns the raw API response when RawOutput is set' -Skip:(-not $script:ConfigAvailable) {
+        Add-PiHoleList -PiHoleServer $script:PiHoleServer -Password $script:PiHoleToken -IgnoreSsl $script:PiHoleIgnoreSsl -Address $script:TestListAddress -Type Block | Out-Null
+
+        $result = Update-PiHoleList -PiHoleServer $script:PiHoleServer -Password $script:PiHoleToken -IgnoreSsl $script:PiHoleIgnoreSsl -Address $script:TestListAddress -Type Block -Comment 'raw output test' -RawOutput $true
+        $result | Format-List | Out-String | Write-Host
+
+        $result.lists[0].comment | Should -Be 'raw output test'
+
+        Remove-PiHoleList -PiHoleServer $script:PiHoleServer -Password $script:PiHoleToken -IgnoreSsl $script:PiHoleIgnoreSsl -Address $script:TestListAddress -Type Block -Confirm:$false | Out-Null
+    }
+
+    It 'errors when neither Comment, Group, nor Enabled is specified' -Skip:(-not $script:ConfigAvailable) {
+        Add-PiHoleList -PiHoleServer $script:PiHoleServer -Password $script:PiHoleToken -IgnoreSsl $script:PiHoleIgnoreSsl -Address $script:TestListAddress -Type Block | Out-Null
+
+        $result = Update-PiHoleList -PiHoleServer $script:PiHoleServer -Password $script:PiHoleToken -IgnoreSsl $script:PiHoleIgnoreSsl -Address $script:TestListAddress -Type Block -ErrorVariable errOut -ErrorAction SilentlyContinue
+
+        $errOut | Should -Not -BeNullOrEmpty
+
+        Remove-PiHoleList -PiHoleServer $script:PiHoleServer -Password $script:PiHoleToken -IgnoreSsl $script:PiHoleIgnoreSsl -Address $script:TestListAddress -Type Block -Confirm:$false | Out-Null
+    }
+
+    It 'errors when the list does not exist' -Skip:(-not $script:ConfigAvailable) {
+        $result = Update-PiHoleList -PiHoleServer $script:PiHoleServer -Password $script:PiHoleToken -IgnoreSsl $script:PiHoleIgnoreSsl -Address 'https://example.com/does-not-exist.txt' -Type Block -Comment 'irrelevant' -ErrorVariable errOut -ErrorAction SilentlyContinue
+
+        $errOut | Should -Not -BeNullOrEmpty
+    }
+
+    It 'errors when given a bad password' -Skip:(-not $script:ConfigAvailable) {
+        Add-PiHoleList -PiHoleServer $script:PiHoleServer -Password $script:PiHoleToken -IgnoreSsl $script:PiHoleIgnoreSsl -Address $script:TestListAddress -Type Block | Out-Null
+
+        $result = Update-PiHoleList -PiHoleServer $script:PiHoleServer -Password 'definitely-not-the-real-token' -IgnoreSsl $script:PiHoleIgnoreSsl -Address $script:TestListAddress -Type Block -Comment 'irrelevant' -ErrorVariable errOut -ErrorAction SilentlyContinue
+
+        $errOut | Should -Not -BeNullOrEmpty
+    }
+}