diff --git a/google/genai/_gaos/types/interactions/model.py b/google/genai/_gaos/types/interactions/model.py
index 360b59f16..ddd15d756 100644
--- a/google/genai/_gaos/types/interactions/model.py
+++ b/google/genai/_gaos/types/interactions/model.py
@@ -66,6 +66,10 @@
         "gemini-3.7-flash",
         # Our most intelligent model for sustained frontier performance in agentic and coding tasks.
         "gemini-3.8-flash",
+        # Gemini 3.8 Flash TTS - Flagship TTS model for Voice Design and dual-speaker screenplay control. Prompt custom vocal personas, direct line-by-line delivery, and add vocal bursts.
+        "gemini-3.8-flash-tts",
+        # Gemini 3.8 Flash Lite TTS - High-speed and cost-efficient, ideal for rapid dubbing, media localization, and high-throughput voice agents. Direct replacement for gemini-3.1-flash-tts-preview.
+        "gemini-3.8-flash-lite-tts",
         # Our low-latency, music generation model optimized for high-fidelity audio clips and precise rhythmic control.
         "lyria-3-clip-preview",
         # Our advanced, full-song generative model with deep compositional understanding, optimized for precise structural control and complex transitions across diverse musical styles.