diff --git a/lib/ruby_llm/configuration.rb b/lib/ruby_llm/configuration.rb
index c1f93ed1b..21ba190d3 100644
--- a/lib/ruby_llm/configuration.rb
+++ b/lib/ruby_llm/configuration.rb
@@ -14,6 +14,7 @@ class Configuration
                   :vertexai_project_id,
                   :vertexai_location,
                   :deepseek_api_key,
+                  :deepseek_api_base,
                   :perplexity_api_key,
                   :bedrock_api_key,
                   :bedrock_secret_key,
diff --git a/lib/ruby_llm/providers/deepseek.rb b/lib/ruby_llm/providers/deepseek.rb
index 41e07bfc8..1dbcc69fd 100644
--- a/lib/ruby_llm/providers/deepseek.rb
+++ b/lib/ruby_llm/providers/deepseek.rb
@@ -7,7 +7,7 @@ class DeepSeek < OpenAI
       include DeepSeek::Chat
 
       def api_base
-        'https://api.deepseek.com'
+        @config.deepseek_api_base || 'https://api.deepseek.com'
       end
 
       def headers
diff --git a/spec/support/rubyllm_configuration.rb b/spec/support/rubyllm_configuration.rb
index 888b3a022..2a1282b44 100644
--- a/spec/support/rubyllm_configuration.rb
+++ b/spec/support/rubyllm_configuration.rb
@@ -11,6 +11,7 @@
       config.anthropic_api_key = ENV.fetch('ANTHROPIC_API_KEY', 'test')
       config.gemini_api_key = ENV.fetch('GEMINI_API_KEY', 'test')
       config.deepseek_api_key = ENV.fetch('DEEPSEEK_API_KEY', 'test')
+      config.deepseek_api_base = ENV.fetch('DEEPSEEK_API_BASE', nil)
       config.perplexity_api_key = ENV.fetch('PERPLEXITY_API_KEY', 'test')
       config.openrouter_api_key = ENV.fetch('OPENROUTER_API_KEY', 'test')
       config.xai_api_key = ENV.fetch('XAI_API_KEY', 'test')