diff --git a/Library/Homebrew/dev-cmd/test-bot.rb b/Library/Homebrew/dev-cmd/test-bot.rb
index 45eae7e19ed49..3697d840ff7f5 100755
--- a/Library/Homebrew/dev-cmd/test-bot.rb
+++ b/Library/Homebrew/dev-cmd/test-bot.rb
@@ -25,7 +25,8 @@ class TestBotCmd < AbstractCommand
         switch "--build-from-source",
                description: "Build from source rather than building bottles."
         switch "--build-dependents-from-source",
-               description: "Build dependents from source rather than testing bottles."
+               description: "Build a limited set of dependents from source in addition to testing bottles. " \
+                            "Up to 10 per formula per shard, prioritising popular dependents in a sharded group."
         switch "--junit",
                description: "generate a JUnit XML test results file."
         switch "--keep-old",
diff --git a/Library/Homebrew/test/test_bot/formulae_dependents_spec.rb b/Library/Homebrew/test/test_bot/formulae_dependents_spec.rb
index 8fe436f34d104..9183a27716ba7 100644
--- a/Library/Homebrew/test/test_bot/formulae_dependents_spec.rb
+++ b/Library/Homebrew/test/test_bot/formulae_dependents_spec.rb
@@ -54,4 +54,74 @@
       expect(formulae_dependents.dependents_for_shard([[dependent, dependent.deps.to_a]], "2/2")).to be_empty
     end
   end
+
+  describe "#split_source_dependents" do
+    let(:dependents) { dependents_hash.values }
+    let(:dependents_hash) do
+      14.downto(6).to_h do |i|
+        f = formula "dependent-#{i}" do
+          T.bind(self, T.class_of(Formula))
+          url "https://brew.sh/dependent-#{i}/1.0.tar.gz"
+          depends_on "dependency"
+        end
+        [i, [f, f.deps.to_a]]
+      end
+    end
+
+    before do
+      stub_formula_loader(
+        formula("dependency") do
+          T.bind(self, T.class_of(Formula))
+          url "https://brew.sh/dependency/1.0.tar.gz"
+        end,
+      )
+      allow(Homebrew::API::Analytics).to receive(:fetch).with("install", 90).and_return({
+        "items" => 1.upto(20).map { |i| { "number" => i, "formula" => "dependent-#{i}" } },
+      })
+      allow(formulae_dependents).to receive_messages(
+        build_dependent_from_source?: true,
+        bottled_or_built?:            true,
+      )
+    end
+
+    it "does not source build dependents with unbottled dependency" do
+      unbottled_dependency = formula "unbottled-dependency" do
+        T.bind(self, T.class_of(Formula))
+        url "https://brew.sh/unbottled-dependency/1.0.tar.gz"
+        depends_on "dependency"
+      end
+      stub_formula_loader unbottled_dependency
+      allow(formulae_dependents).to receive(:bottled_or_built?).with(unbottled_dependency, []).and_return(false)
+
+      source_dependents = dependents_hash.values
+      dependent_with_unbottled_dep = formula "dependent-5" do
+        T.bind(self, T.class_of(Formula))
+        url "https://brew.sh/dependent-5/1.0.tar.gz"
+        depends_on "dependency"
+        depends_on "unbottled-dependency"
+      end
+      not_source_dependent = [dependent_with_unbottled_dep, dependent_with_unbottled_dep.deps.to_a]
+      dependents_hash[5] = not_source_dependent
+
+      expect(formulae_dependents.split_source_dependents(dependents)).to eq [
+        source_dependents,
+        [not_source_dependent],
+      ]
+    end
+
+    it "limits total source build dependents to upper bound and orders on analytics" do
+      expect(formulae_dependents.split_source_dependents(dependents, 1)).to eq [
+        [dependents_hash.fetch(6)],
+        7.upto(14).map { dependents_hash.fetch(it) },
+      ]
+      expect(formulae_dependents.split_source_dependents(dependents, 5)).to eq [
+        6.upto(10).map { dependents_hash.fetch(it) },
+        11.upto(14).map { dependents_hash.fetch(it) },
+      ]
+      expect(formulae_dependents.split_source_dependents(dependents, 7)).to eq [
+        6.upto(12).map { dependents_hash.fetch(it) },
+        13.upto(14).map { dependents_hash.fetch(it) },
+      ]
+    end
+  end
 end
diff --git a/Library/Homebrew/test_bot/formulae_dependents.rb b/Library/Homebrew/test_bot/formulae_dependents.rb
index db97f1db3733a..67b453c152c8a 100644
--- a/Library/Homebrew/test_bot/formulae_dependents.rb
+++ b/Library/Homebrew/test_bot/formulae_dependents.rb
@@ -4,6 +4,9 @@
 module Homebrew
   module TestBot
     class FormulaeDependents < TestFormulae
+      MAX_DEPENDENTS_FROM_SOURCE = 10
+      private_constant :MAX_DEPENDENTS_FROM_SOURCE
+
       DependentWithDependencies = T.type_alias { [Formula, T::Array[Dependency]] }
       private_constant :DependentWithDependencies
 
@@ -162,6 +165,51 @@ def dependents_for_shard(dependents, shard)
         shards.fetch(shard_index - 1).sort_by { |dependent, _| dependent.full_name }
       end
 
+      sig {
+        params(
+          dependents: T::Array[DependentWithDependencies],
+          max:        Integer,
+        ).returns([T::Array[DependentWithDependencies], T::Array[DependentWithDependencies]])
+      }
+      def split_source_dependents(dependents, max = MAX_DEPENDENTS_FROM_SOURCE)
+        source_dependents, dependents = dependents.partition do |dependent, deps|
+          next false unless build_dependent_from_source?(dependent)
+
+          deps.all? do |d|
+            bottled_or_built?(d.to_formula, @dependent_testing_formulae)
+          end
+        end
+
+        return [source_dependents, dependents] if source_dependents.count <= max
+
+        ohai "Only source building #{max} of #{source_dependents.count} dependents"
+
+        @formula_install_ranks ||= T.let(begin
+          analytics = begin
+            require "api/analytics"
+            Homebrew::API::Analytics.fetch "install", 90
+          rescue ArgumentError
+            {}
+          end
+          analytics["items"].to_a.each_with_object({}) do |item, hash|
+            formula = item["formula"]
+            number = item["number"]
+            next if formula.blank? || number.blank?
+
+            hash[formula.to_s] = number.to_i
+          end
+        end, T.nilable(T::Hash[String, Integer]))
+
+        if @formula_install_ranks.present?
+          last = @formula_install_ranks.each_value.max.to_i + 1
+          source_dependents.sort_by! do |dependent, _|
+            [@formula_install_ranks.fetch(dependent.full_name, last), dependent.full_name]
+          end
+        end
+        dependents.concat(source_dependents.slice!(max..).to_a)
+        [source_dependents, dependents]
+      end
+
       private
 
       sig { params(installable_bottles: T::Array[String], args: Homebrew::Cmd::TestBotCmd::Args).void }
@@ -249,16 +297,12 @@ def dependents_for_formula(formula, formula_name, args:)
         dependents.reject! { |dependent, _| @tested_dependents.include?(dependent.full_name) }
 
         # Split into dependents that we could potentially be building from source and those
-        # we should not. The criteria is that a dependent must have bottled dependencies, and
-        # either the `--build-dependents-from-source` flag was passed or a dependent has no
-        # bottle on the current OS.
-        source_dependents, dependents = dependents.partition do |dependent, deps|
-          next false unless build_dependent_from_source?(dependent)
-
-          all_deps_bottled_or_built = deps.all? do |d|
-            bottled_or_built?(d.to_formula, @dependent_testing_formulae)
-          end
-          args.build_dependents_from_source? && all_deps_bottled_or_built
+        # we should not. The criteria is that a dependent must have bottled dependencies and
+        # the `--build-dependents-from-source` flag was passed. Total source build dependents
+        # are limited per formula per shard to avoid overly long CI runtime.
+        source_dependents = []
+        if args.build_dependents_from_source?
+          source_dependents, dependents = split_source_dependents(dependents)
         end
 
         # From the non-source list, get rid of any dependents we are only a build dependency to
diff --git a/completions/fish/brew.fish b/completions/fish/brew.fish
index 93f258d1c1886..5f0be55122281 100644
--- a/completions/fish/brew.fish
+++ b/completions/fish/brew.fish
@@ -1943,7 +1943,7 @@ __fish_brew_complete_arg 'test' -a '(__fish_brew_suggest_formulae_installed)'
 
 __fish_brew_complete_cmd 'test-bot' 'Tests the full lifecycle of a Homebrew change to a tap (Git repository)'
 __fish_brew_complete_arg 'test-bot' -l added-formulae -d 'Use these added formulae rather than running the formulae detection steps'
-__fish_brew_complete_arg 'test-bot' -l build-dependents-from-source -d 'Build dependents from source rather than testing bottles'
+__fish_brew_complete_arg 'test-bot' -l build-dependents-from-source -d 'Build a limited set of dependents from source in addition to testing bottles. Up to 10 per formula per shard, prioritising popular dependents in a sharded group'
 __fish_brew_complete_arg 'test-bot' -l build-from-source -d 'Build from source rather than building bottles'
 __fish_brew_complete_arg 'test-bot' -l cleanup -d 'Clean all state from the Homebrew directory. Use with care!'
 __fish_brew_complete_arg 'test-bot' -l debug -d 'Display any debugging information'
diff --git a/completions/zsh/_brew b/completions/zsh/_brew
index e813682adaba4..bb07bb794613a 100644
--- a/completions/zsh/_brew
+++ b/completions/zsh/_brew
@@ -2511,7 +2511,7 @@ _brew_test() {
 _brew_test_bot() {
   _arguments \
     '(--only-formulae-detect)--added-formulae[Use these added formulae rather than running the formulae detection steps]' \
-    '--build-dependents-from-source[Build dependents from source rather than testing bottles]' \
+    '--build-dependents-from-source[Build a limited set of dependents from source in addition to testing bottles. Up to 10 per formula per shard, prioritising popular dependents in a sharded group]' \
     '--build-from-source[Build from source rather than building bottles]' \
     '--cleanup[Clean all state from the Homebrew directory. Use with care!]' \
     '--debug[Display any debugging information]' \
diff --git a/docs/Manpage.md b/docs/Manpage.md
index 18ec57f925a1a..47ef469572772 100644
--- a/docs/Manpage.md
+++ b/docs/Manpage.md
@@ -3750,7 +3750,9 @@ and Linux workers.
 
 `--build-dependents-from-source`
 
-: Build dependents from source rather than testing bottles.
+: Build a limited set of dependents from source in addition to testing bottles.
+  Up to 10 per formula per shard, prioritising popular dependents in a sharded
+  group.
 
 `--junit`
 
diff --git a/manpages/brew.1 b/manpages/brew.1
index 7fad4b9a78cf7..20f68c3101963 100644
--- a/manpages/brew.1
+++ b/manpages/brew.1
@@ -2360,7 +2360,7 @@ Don\[u2019]t check if the local system is set up correctly\.
 Build from source rather than building bottles\.
 .TP
 \fB\-\-build\-dependents\-from\-source\fP
-Build dependents from source rather than testing bottles\.
+Build a limited set of dependents from source in addition to testing bottles\. Up to 10 per formula per shard, prioritising popular dependents in a sharded group\.
 .TP
 \fB\-\-junit\fP
 generate a JUnit XML test results file\.