diff --git a/model/renderers/deepseek3.go b/model/renderers/deepseek3.go
new file mode 100644
index 000000000..c52b08049
--- /dev/null
+++ b/model/renderers/deepseek3.go
@@ -0,0 +1,115 @@
+package renderers
+
+import (
+	"encoding/json"
+	"strings"
+
+	"github.com/ollama/ollama/api"
+)
+
+type DeepSeekRenderer struct {
+	isThinking bool
+}
+
+func (r *DeepSeekRenderer) Render(messages []api.Message, tools []api.Tool, thinkValue *api.ThinkValue) (string, error) {
+	var sb strings.Builder
+
+	// thinking is enabled: model must support it AND user must request it (true)
+	enableThinking := r.isThinking && (thinkValue != nil && thinkValue.Bool())
+
+	var systemPrompt strings.Builder
+	var conversationMessages []api.Message
+	isFirstSystemPrompt := true
+
+	for _, message := range messages {
+		if message.Role == "system" {
+			if isFirstSystemPrompt {
+				systemPrompt.WriteString(message.Content)
+				isFirstSystemPrompt = false
+			} else {
+				systemPrompt.WriteString("\n\n" + message.Content)
+			}
+		} else {
+			conversationMessages = append(conversationMessages, message)
+		}
+	}
+
+	sb.WriteString("<｜begin▁of▁sentence｜>" + systemPrompt.String())
+
+	isLastUser := false
+	isToolContext := false
+
+	for _, message := range conversationMessages {
+		switch message.Role {
+		case "user":
+			isToolContext = false
+			isLastUser = true
+			sb.WriteString("<｜User｜>" + message.Content)
+
+		case "assistant":
+			if len(message.ToolCalls) > 0 {
+				if isLastUser {
+					sb.WriteString("<｜Assistant｜></think>")
+				}
+				isLastUser = false
+				isToolContext = false
+
+				if message.Content != "" {
+					sb.WriteString(message.Content)
+				}
+
+				sb.WriteString("<｜tool▁calls▁begin｜>")
+
+				for _, toolCall := range message.ToolCalls {
+					sb.WriteString("<｜tool▁call▁begin｜>" + toolCall.Function.Name + "<｜tool▁sep｜>")
+
+					argsJSON, _ := json.Marshal(toolCall.Function.Arguments)
+					sb.WriteString(string(argsJSON))
+					sb.WriteString("<｜tool▁call▁end｜>")
+				}
+
+				sb.WriteString("<｜tool▁calls▁end｜><｜end▁of▁sentence｜>")
+			} else {
+				if isLastUser {
+					sb.WriteString("<｜Assistant｜>")
+					if enableThinking {
+						sb.WriteString("<think>")
+					} else {
+						sb.WriteString("</think>")
+					}
+				}
+				isLastUser = false
+
+				content := message.Content
+				if isToolContext {
+					sb.WriteString(content + "<｜end▁of▁sentence｜>")
+					isToolContext = false
+				} else {
+					if strings.Contains(content, "</think>") {
+						parts := strings.SplitN(content, "</think>", 2)
+						if len(parts) > 1 {
+							content = parts[1]
+						}
+					}
+					sb.WriteString(content + "<｜end▁of▁sentence｜>")
+				}
+			}
+
+		case "tool":
+			isLastUser = false
+			isToolContext = true
+			sb.WriteString("<｜tool▁output▁begin｜>" + message.Content + "<｜tool▁output▁end｜>")
+		}
+	}
+
+	if isLastUser && !isToolContext {
+		sb.WriteString("<｜Assistant｜>")
+		if enableThinking {
+			sb.WriteString("<think>")
+		} else {
+			sb.WriteString("</think>")
+		}
+	}
+
+	return sb.String(), nil
+}
diff --git a/model/renderers/deepseek3_test.go b/model/renderers/deepseek3_test.go
new file mode 100644
index 000000000..f389881c7
--- /dev/null
+++ b/model/renderers/deepseek3_test.go
@@ -0,0 +1,288 @@
+package renderers
+
+import (
+	"testing"
+
+	"github.com/google/go-cmp/cmp"
+
+	"github.com/ollama/ollama/api"
+)
+
+func TestDeepSeekRenderer(t *testing.T) {
+	tests := []struct {
+		name       string
+		messages   []api.Message
+		tools      []api.Tool
+		thinkValue *api.ThinkValue
+		expected   string
+	}{
+		{
+			name: "basic user message",
+			messages: []api.Message{
+				{Role: "user", Content: "Hello, how are you?"},
+			},
+			thinkValue: &api.ThinkValue{Value: false},
+			expected:   `<｜begin▁of▁sentence｜><｜User｜>Hello, how are you?<｜Assistant｜></think>`,
+		},
+		{
+			name: "basic with system message",
+			messages: []api.Message{
+				{Role: "system", Content: "You are a helpful assistant."},
+				{Role: "user", Content: "Hello, how are you?"},
+			},
+			thinkValue: &api.ThinkValue{Value: false},
+			expected:   `<｜begin▁of▁sentence｜>You are a helpful assistant.<｜User｜>Hello, how are you?<｜Assistant｜></think>`,
+		},
+		{
+			name: "multiple system messages",
+			messages: []api.Message{
+				{Role: "system", Content: "First instruction"},
+				{Role: "system", Content: "Second instruction"},
+				{Role: "user", Content: "Hello"},
+			},
+			thinkValue: &api.ThinkValue{Value: false},
+			expected: `<｜begin▁of▁sentence｜>First instruction
+
+Second instruction<｜User｜>Hello<｜Assistant｜></think>`,
+		},
+		{
+			name: "thinking enabled",
+			messages: []api.Message{
+				{Role: "user", Content: "Hello, how are you?"},
+			},
+			thinkValue: &api.ThinkValue{Value: true},
+			expected:   `<｜begin▁of▁sentence｜><｜User｜>Hello, how are you?<｜Assistant｜><think>`,
+		},
+		{
+			name: "thinking enabled with system",
+			messages: []api.Message{
+				{Role: "system", Content: "You are a helpful assistant."},
+				{Role: "user", Content: "Hello, how are you?"},
+			},
+			thinkValue: &api.ThinkValue{Value: true},
+			expected:   `<｜begin▁of▁sentence｜>You are a helpful assistant.<｜User｜>Hello, how are you?<｜Assistant｜><think>`,
+		},
+		{
+			name: "conversation with assistant response",
+			messages: []api.Message{
+				{Role: "user", Content: "What is the capital of France?"},
+				{Role: "assistant", Content: "The capital of France is Paris."},
+				{Role: "user", Content: "Fantastic!"},
+			},
+			thinkValue: &api.ThinkValue{Value: false},
+			expected:   `<｜begin▁of▁sentence｜><｜User｜>What is the capital of France?<｜Assistant｜></think>The capital of France is Paris.<｜end▁of▁sentence｜><｜User｜>Fantastic!<｜Assistant｜></think>`,
+		},
+		{
+			name: "assistant with tool calls",
+			messages: []api.Message{
+				{Role: "user", Content: "What's the weather?"},
+				{
+					Role: "assistant",
+					ToolCalls: []api.ToolCall{
+						{
+							Function: api.ToolCallFunction{
+								Name: "get_weather",
+								Arguments: api.ToolCallFunctionArguments{
+									"location": "Paris",
+								},
+							},
+						},
+					},
+				},
+			},
+			thinkValue: &api.ThinkValue{Value: false},
+			expected:   `<｜begin▁of▁sentence｜><｜User｜>What's the weather?<｜Assistant｜></think><｜tool▁calls▁begin｜><｜tool▁call▁begin｜>get_weather<｜tool▁sep｜>{"location":"Paris"}<｜tool▁call▁end｜><｜tool▁calls▁end｜><｜end▁of▁sentence｜>`,
+		},
+		{
+			name: "assistant with content and tool calls",
+			messages: []api.Message{
+				{Role: "user", Content: "What's the weather in Paris?"},
+				{
+					Role:    "assistant",
+					Content: "I'll check the weather for you.",
+					ToolCalls: []api.ToolCall{
+						{
+							Function: api.ToolCallFunction{
+								Name: "get_weather",
+								Arguments: api.ToolCallFunctionArguments{
+									"location": "Paris",
+								},
+							},
+						},
+					},
+				},
+			},
+			thinkValue: &api.ThinkValue{Value: false},
+			expected:   `<｜begin▁of▁sentence｜><｜User｜>What's the weather in Paris?<｜Assistant｜></think>I'll check the weather for you.<｜tool▁calls▁begin｜><｜tool▁call▁begin｜>get_weather<｜tool▁sep｜>{"location":"Paris"}<｜tool▁call▁end｜><｜tool▁calls▁end｜><｜end▁of▁sentence｜>`,
+		},
+		{
+			name: "tool response",
+			messages: []api.Message{
+				{Role: "user", Content: "What's the weather?"},
+				{
+					Role: "assistant",
+					ToolCalls: []api.ToolCall{
+						{
+							Function: api.ToolCallFunction{
+								Name: "get_weather",
+								Arguments: api.ToolCallFunctionArguments{
+									"location": "Paris",
+								},
+							},
+						},
+					},
+				},
+				{Role: "tool", Content: "Temperature: 22°C, Sunny"},
+			},
+			thinkValue: &api.ThinkValue{Value: false},
+			expected:   `<｜begin▁of▁sentence｜><｜User｜>What's the weather?<｜Assistant｜></think><｜tool▁calls▁begin｜><｜tool▁call▁begin｜>get_weather<｜tool▁sep｜>{"location":"Paris"}<｜tool▁call▁end｜><｜tool▁calls▁end｜><｜end▁of▁sentence｜><｜tool▁output▁begin｜>Temperature: 22°C, Sunny<｜tool▁output▁end｜>`,
+		},
+		{
+			name: "multiple tool calls",
+			messages: []api.Message{
+				{Role: "user", Content: "Get weather for Paris and London"},
+				{
+					Role: "assistant",
+					ToolCalls: []api.ToolCall{
+						{
+							Function: api.ToolCallFunction{
+								Name: "get_weather",
+								Arguments: api.ToolCallFunctionArguments{
+									"location": "Paris",
+								},
+							},
+						},
+						{
+							Function: api.ToolCallFunction{
+								Name: "get_weather",
+								Arguments: api.ToolCallFunctionArguments{
+									"location": "London",
+								},
+							},
+						},
+					},
+				},
+				{Role: "tool", Content: "Paris: 22°C, Sunny"},
+				{Role: "tool", Content: "London: 18°C, Cloudy"},
+			},
+			thinkValue: &api.ThinkValue{Value: false},
+			expected:   `<｜begin▁of▁sentence｜><｜User｜>Get weather for Paris and London<｜Assistant｜></think><｜tool▁calls▁begin｜><｜tool▁call▁begin｜>get_weather<｜tool▁sep｜>{"location":"Paris"}<｜tool▁call▁end｜><｜tool▁call▁begin｜>get_weather<｜tool▁sep｜>{"location":"London"}<｜tool▁call▁end｜><｜tool▁calls▁end｜><｜end▁of▁sentence｜><｜tool▁output▁begin｜>Paris: 22°C, Sunny<｜tool▁output▁end｜><｜tool▁output▁begin｜>London: 18°C, Cloudy<｜tool▁output▁end｜>`,
+		},
+		{
+			name: "content with </think> tag removal",
+			messages: []api.Message{
+				{Role: "user", Content: "Think about this"},
+				{Role: "assistant", Content: "I'm thinking about this.</think>The answer is 42."},
+			},
+			thinkValue: &api.ThinkValue{Value: false},
+			expected:   `<｜begin▁of▁sentence｜><｜User｜>Think about this<｜Assistant｜></think>The answer is 42.<｜end▁of▁sentence｜>`,
+		},
+		{
+			name: "empty system message",
+			messages: []api.Message{
+				{Role: "system", Content: ""},
+				{Role: "user", Content: "Hello"},
+			},
+			thinkValue: &api.ThinkValue{Value: false},
+			expected:   `<｜begin▁of▁sentence｜><｜User｜>Hello<｜Assistant｜></think>`,
+		},
+		{
+			name: "empty assistant content",
+			messages: []api.Message{
+				{Role: "user", Content: "Hello"},
+				{Role: "assistant", Content: ""},
+			},
+			thinkValue: &api.ThinkValue{Value: false},
+			expected:   `<｜begin▁of▁sentence｜><｜User｜>Hello<｜Assistant｜></think><｜end▁of▁sentence｜>`,
+		},
+		{
+			name: "special characters",
+			messages: []api.Message{
+				{Role: "user", Content: "What about <|special|> tokens and \"quotes\"?"},
+				{Role: "assistant", Content: "They're handled normally."},
+			},
+			thinkValue: &api.ThinkValue{Value: false},
+			expected:   `<｜begin▁of▁sentence｜><｜User｜>What about <|special|> tokens and "quotes"?<｜Assistant｜></think>They're handled normally.<｜end▁of▁sentence｜>`,
+		},
+		{
+			name: "tool calls with null content",
+			messages: []api.Message{
+				{Role: "user", Content: "Get weather"},
+				{
+					Role: "assistant",
+					ToolCalls: []api.ToolCall{
+						{
+							Function: api.ToolCallFunction{
+								Name: "get_weather",
+								Arguments: api.ToolCallFunctionArguments{
+									"location": "Paris",
+								},
+							},
+						},
+					},
+				},
+			},
+			thinkValue: &api.ThinkValue{Value: false},
+			expected:   `<｜begin▁of▁sentence｜><｜User｜>Get weather<｜Assistant｜></think><｜tool▁calls▁begin｜><｜tool▁call▁begin｜>get_weather<｜tool▁sep｜>{"location":"Paris"}<｜tool▁call▁end｜><｜tool▁calls▁end｜><｜end▁of▁sentence｜>`,
+		},
+		{
+			name: "assistant after tool context",
+			messages: []api.Message{
+				{Role: "user", Content: "Process data"},
+				{
+					Role: "assistant",
+					ToolCalls: []api.ToolCall{
+						{
+							Function: api.ToolCallFunction{
+								Name: "process",
+								Arguments: api.ToolCallFunctionArguments{
+									"data": "test",
+								},
+							},
+						},
+					},
+				},
+				{Role: "tool", Content: "Success"},
+				{Role: "assistant", Content: "Done"},
+			},
+			thinkValue: &api.ThinkValue{Value: false},
+			expected:   `<｜begin▁of▁sentence｜><｜User｜>Process data<｜Assistant｜></think><｜tool▁calls▁begin｜><｜tool▁call▁begin｜>process<｜tool▁sep｜>{"data":"test"}<｜tool▁call▁end｜><｜tool▁calls▁end｜><｜end▁of▁sentence｜><｜tool▁output▁begin｜>Success<｜tool▁output▁end｜>Done<｜end▁of▁sentence｜>`,
+		},
+		{
+			name:       "no messages",
+			messages:   []api.Message{},
+			thinkValue: &api.ThinkValue{Value: false},
+			expected:   `<｜begin▁of▁sentence｜>`,
+		},
+		{
+			name: "only system messages",
+			messages: []api.Message{
+				{Role: "system", Content: "System instruction"},
+			},
+			thinkValue: &api.ThinkValue{Value: false},
+			expected:   `<｜begin▁of▁sentence｜>System instruction`,
+		},
+		{
+			name: "multiple think tags in content",
+			messages: []api.Message{
+				{Role: "user", Content: "Complex question"},
+				{Role: "assistant", Content: "First thought</think>Second thought</think>Final answer"},
+			},
+			thinkValue: &api.ThinkValue{Value: false},
+			expected:   `<｜begin▁of▁sentence｜><｜User｜>Complex question<｜Assistant｜></think>Second thought</think>Final answer<｜end▁of▁sentence｜>`,
+		},
+	}
+
+	renderer := &DeepSeekRenderer{isThinking: true}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			rendered, err := renderer.Render(tt.messages, tt.tools, tt.thinkValue)
+			if err != nil {
+				t.Fatalf("Render() error = %v", err)
+			}
+			if diff := cmp.Diff(tt.expected, rendered); diff != "" {
+				t.Errorf("Render() mismatch (-want +got):\n%s", diff)
+			}
+		})
+	}
+}
diff --git a/model/renderers/renderer.go b/model/renderers/renderer.go
index e3d797a62..e6fede7a5 100644
--- a/model/renderers/renderer.go
+++ b/model/renderers/renderer.go
@@ -59,6 +59,9 @@ func rendererForName(name string) Renderer {
 	case "cogito":
 		renderer := &CogitoRenderer{isThinking: true}
 		return renderer
+	case "deepseek":
+		renderer := &DeepSeekRenderer{isThinking: true}
+		return renderer
 	case "olmo3":
 		renderer := &Olmo3Renderer{UseExtendedSystemMessage: false}
 		return renderer