diff --git a/.changeset/polling-interval-default.md b/.changeset/polling-interval-default.md
new file mode 100644
index 0000000..85dd020
--- /dev/null
+++ b/.changeset/polling-interval-default.md
@@ -0,0 +1,5 @@
+---
+"posthog-ruby": patch
+---
+
+Honor the documented 30s default for `feature_flags_polling_interval`. The resolved default was computed but never passed to the polling timer, so when the option was unset the effective interval was concurrent-ruby's 60s TimerTask default. Definitions now poll every 30s by default as documented; set `feature_flags_polling_interval: 60` to keep the previous effective cadence.
diff --git a/lib/posthog/defaults.rb b/lib/posthog/defaults.rb
index eea7666..d152ec4 100644
--- a/lib/posthog/defaults.rb
+++ b/lib/posthog/defaults.rb
@@ -19,6 +19,7 @@ module Request
 
     module FeatureFlags
       FLAG_REQUEST_TIMEOUT_SECONDS = 3
+      POLLING_INTERVAL_SECONDS = 30
       # Number of retries for a flag request after a transient network error.
       # Flag requests are stateless and cause no server-side mutation, so
       # retrying is safe.
diff --git a/lib/posthog/feature_flags.rb b/lib/posthog/feature_flags.rb
index dde847c..159035c 100644
--- a/lib/posthog/feature_flags.rb
+++ b/lib/posthog/feature_flags.rb
@@ -30,6 +30,7 @@ class FeatureFlagsPoller
     include PostHog::Utils
 
     # @param polling_interval [Integer, nil] Seconds between local feature flag definition polls.
+    #   Defaults to {Defaults::FeatureFlags::POLLING_INTERVAL_SECONDS}.
     # @param secret_key [String, nil] Credential used to fetch local evaluation definitions. Accepts either a
     #   Personal API Key (`phx_...`) or a Project Secret API Key (`phs_...`).
     # @param project_api_key [String] Project API key.
@@ -50,7 +51,7 @@ def initialize(
       flag_definition_cache_provider: nil,
       feature_flag_request_max_retries: nil
     )
-      @polling_interval = polling_interval || 30
+      @polling_interval = polling_interval || Defaults::FeatureFlags::POLLING_INTERVAL_SECONDS
       @secret_key = secret_key
       @project_api_key = project_api_key
       @host = host
@@ -72,7 +73,7 @@ def initialize(
 
       @task =
         Concurrent::TimerTask.new(
-          execution_interval: polling_interval
+          execution_interval: @polling_interval
         ) { _load_feature_flags }
 
       # If no secret_key, disable local evaluation & thus polling for definitions
diff --git a/public_api_snapshot.txt b/public_api_snapshot.txt
index fb26974..3fb6568 100644
--- a/public_api_snapshot.txt
+++ b/public_api_snapshot.txt
@@ -36,6 +36,7 @@ constant PostHog::Defaults::BackoffPolicy::RANDOMIZATION_FACTOR: Float
 module PostHog::Defaults::FeatureFlags
 constant PostHog::Defaults::FeatureFlags::FLAG_REQUEST_MAX_RETRIES: Integer
 constant PostHog::Defaults::FeatureFlags::FLAG_REQUEST_TIMEOUT_SECONDS: Integer
+constant PostHog::Defaults::FeatureFlags::POLLING_INTERVAL_SECONDS: Integer
 constant PostHog::Defaults::MAX_HASH_SIZE: Integer
 module PostHog::Defaults::Message
 constant PostHog::Defaults::Message::MAX_BYTES: Integer
diff --git a/spec/posthog/feature_flag_spec.rb b/spec/posthog/feature_flag_spec.rb
index 287183c..db188e9 100644
--- a/spec/posthog/feature_flag_spec.rb
+++ b/spec/posthog/feature_flag_spec.rb
@@ -5349,4 +5349,33 @@ def flag_called_properties(client, key)
       end
     end
   end
+
+  describe 'definitions polling interval' do
+    before do
+      stub_request(
+        :get,
+        'https://us.i.posthog.com/flags/definitions?token=testsecret&send_cohorts=true'
+      ).to_return(status: 200, body: { flags: [] }.to_json)
+    end
+
+    def timer_task_interval(client)
+      poller = client.instance_variable_get(:@feature_flags_poller)
+      poller.instance_variable_get(:@task).execution_interval
+    end
+
+    it 'defaults to the documented 30 seconds' do
+      client = Client.new(api_key: API_KEY, secret_key: API_KEY, test_mode: true)
+
+      expect(timer_task_interval(client)).to eq(30)
+    end
+
+    it 'uses feature_flags_polling_interval when provided' do
+      client = Client.new(
+        api_key: API_KEY, secret_key: API_KEY, test_mode: true,
+        feature_flags_polling_interval: 15
+      )
+
+      expect(timer_task_interval(client)).to eq(15)
+    end
+  end
 end