diff --git a/lib/bundler/cli/outdated.rb b/lib/bundler/cli/outdated.rb
index 857caf0a03..2075fe83c8 100644
--- a/lib/bundler/cli/outdated.rb
+++ b/lib/bundler/cli/outdated.rb
@@ -172,6 +172,8 @@ module Bundler
     end
 
     def retrieve_active_spec(strict, definition, current_spec)
+      return unless current_spec.match_platform(Bundler.local_platform)
+
       if strict
         active_spec = definition.find_resolved_spec(current_spec)
       else
diff --git a/lib/bundler/definition.rb b/lib/bundler/definition.rb
index 562b1a0ed1..8f85b2ccec 100644
--- a/lib/bundler/definition.rb
+++ b/lib/bundler/definition.rb
@@ -113,7 +113,7 @@ module Bundler
       end
       @unlocking ||= @unlock[:ruby] ||= (!@locked_ruby_version ^ !@ruby_version)
 
-      add_current_platform unless Bundler.frozen_bundle?
+      add_platforms unless Bundler.frozen_bundle?
 
       converge_path_sources_to_gemspec_sources
       @path_changes = converge_paths
@@ -543,6 +543,12 @@ module Bundler
 
   private
 
+    def add_platforms
+      (@dependencies.flat_map(&:expanded_platforms) + current_platforms).uniq.each do |platform|
+        add_platform(platform)
+      end
+    end
+
     def current_platforms
       current_platform = Bundler.local_platform
       platforms = []
diff --git a/spec/bundler/install/gemfile/platform_spec.rb b/spec/bundler/install/gemfile/platform_spec.rb
index c096531398..4cbf238416 100644
--- a/spec/bundler/install/gemfile/platform_spec.rb
+++ b/spec/bundler/install/gemfile/platform_spec.rb
@@ -372,7 +372,7 @@ RSpec.describe "bundle install with platform conditionals" do
     expect(out).not_to match(/Could not find gem 'some_gem/)
   end
 
-  it "prints a helpful warning when a dependency is unused on any platform" do
+  it "resolves all platforms by default and without warning messages" do
     simulate_platform "ruby"
     simulate_ruby_engine "ruby"
 
@@ -384,9 +384,27 @@ RSpec.describe "bundle install with platform conditionals" do
 
     bundle! "install"
 
-    expect(err).to include <<-O.strip
-The dependency #{Gem::Dependency.new("rack", ">= 0")} will be unused by any of the platforms Bundler is installing for. Bundler is installing for ruby but the dependency is only for x86-mingw32, x86-mswin32, x64-mingw32, java. To add those platforms to the bundle, run `bundle lock --add-platform x86-mingw32 x86-mswin32 x64-mingw32 java`.
-    O
+    expect(err).to be_empty
+
+    lockfile_should_be <<-L
+      GEM
+        remote: #{file_uri_for(gem_repo1)}/
+        specs:
+          rack (1.0.0)
+
+      PLATFORMS
+        java
+        ruby
+        x64-mingw32
+        x86-mingw32
+        x86-mswin32
+
+      DEPENDENCIES
+        rack
+
+      BUNDLED WITH
+         #{Bundler::VERSION}
+    L
   end
 
   context "when disable_platform_warnings is true" do
diff --git a/spec/bundler/runtime/require_spec.rb b/spec/bundler/runtime/require_spec.rb
index 958d7cf26a..016fc14dfe 100644
--- a/spec/bundler/runtime/require_spec.rb
+++ b/spec/bundler/runtime/require_spec.rb
@@ -425,7 +425,7 @@ RSpec.describe "Bundler.require with platform specific dependencies" do
       source "#{file_uri_for(gem_repo1)}"
 
       platforms :#{not_local_tag} do
-        gem "fail", :require => "omgomg"
+        gem "platform_specific", :require => "omgomg"
       end
 
       gem "rack", "1.0.0"