diff --git a/README.md b/README.md
index 3a1b3ce..084c7a6 100644
--- a/README.md
+++ b/README.md
@@ -22,13 +22,15 @@ languages.
 - **User-Friendly CLI**: Simple and intuitive command-line interface
 for easy usage.
 - **Markdown Reports**: Outputs code reviews in markdown for flexible viewing
-and integration.
+  and integration.
+- **Configurable Model**: Use the default OpenAI model, or choose another
 
 ![Screenshot](./assets/cadre-screenshot.png)
 
 ## Review Details
 
-Each diff file is reviewed in isolation.  Code reviews are broken into several sections:
+Each diff file is reviewed in isolation.  Code reviews are broken into several
+sections:
 
 - Technical Accuracy
 - Best Practices
@@ -81,6 +83,8 @@ or
 ```bash
 # Run the application with a GitHub pull request URL and API key
 ./cadre --url=https://github.com/user/repo/pull/123 --key=your_api_key
+./cadre --url=https://github.com/a/repo/pull/123 --model gpt-3.5-turbo-instruct
+
 ```
 
 ### Command-Line Switches
@@ -88,8 +92,18 @@ or
 - `--url`: The GitHub pull request URL. Example: `--url=https://github.com/user/repo/pull/123`
 - `--key`: Your OpenAI API key. You can also set this using the `OPENAI_API_KEY`
 environment variable. Example: `--key=your_api_key`
+- `--model`: You can specify the (OpenAI Model)[https://platform.openai.
+  com/docs/models] to use by passing it here.
 - `--help`: Show help information.
 
+## Configuring The Model
+
+You can tell Cadre what OpenAI Model to use by passing it via
+the command line argument `--model` or by setting the `CADRE_AI_MODEL`
+environment variable.
+
+The most common models are: `gpt-4` and `gpt-3.5-turbo-1106`
+
 ### Running Tests ✔️
 
 ```bash
diff --git a/main.go b/main.go
index ef3f497..afa25cc 100644
--- a/main.go
+++ b/main.go
@@ -13,9 +13,15 @@ import (
 	"github.com/mkideal/cli"
 )
 
+const (
+	DefaultFilePerms   = 0o644
+	DefaultOpenAIModel = "gpt-4-1106-preview"
+)
+
 type argT struct {
-	URL    string `cli:"*url" usage:"The GitHub pull request URL"`
-	ApiKey string `cli:"key" env:"OPENAI_API_KEY"  usage:"Your OpenAI API key. Leave this blank to use environment variable OPENAI_API_KEY"`
+	URL             string `cli:"*url" usage:"The GitHub pull request URL"`
+	ApiKey          string `cli:"key" env:"OPENAI_API_KEY"  usage:"Your OpenAI API key. Leave this blank to use environment variable OPENAI_API_KEY"`
+	CompletionModel string `cli:"model" env:"CRITIC_AI_MODEL" usage:"The OpenAI API model to use for code reviews."`
 }
 
 type ReviewedDiff struct {
@@ -43,50 +49,55 @@ func main() {
 		}
 
 		fmt.Printf("📡 Getting pull request from GitHub...\n")
-
 		parsedDiffFiles, err := processPullRequest(mergedArgs.URL, &GithubDiffClient{})
-
 		if err != nil {
 			return err
 		}
 
 		fmt.Printf("\n⌛  Processing %d diff files.  This may take a while...\n\n", len(parsedDiffFiles))
-
-		reviews, err := getCodeReviews(parsedDiffFiles, "gpt-4-1106-preview", mergedArgs.ApiKey, &OpenAICompletionService{})
+		reviews, err := getCodeReviews(
+			parsedDiffFiles,
+			argv.CompletionModel,
+			mergedArgs.ApiKey,
+			&OpenAICompletionService{},
+		)
 		if err != nil {
 			return err
 		}
 
-		for _, review := range reviews {
+		saveReviews(reviews)
+		fmt.Println("Done! 🏁")
 
-			if review.Error != nil {
-				fmt.Printf("⚠️ couldn't get the review for %s:  %s\n",
-					path.Base(review.Diff.FilePathNew),
-					review.Error,
-				)
+		return nil
+	}))
+}
 
-				continue
-			}
+func saveReviews(reviews []ReviewedDiff) {
+	for _, review := range reviews {
 
-			filename := path.Base(review.Diff.FilePathNew) + ".md"
+		if review.Error != nil {
+			fmt.Printf("⚠️ couldn't get the review for %s:  %s\n",
+				path.Base(review.Diff.FilePathNew),
+				review.Error,
+			)
 
-			err := saveReviewToFile(filename, review.Review)
+			continue
+		}
 
-			if err != nil {
-				fmt.Printf("⚠️ couldn't save the review for %s:  %s\n",
-					filename,
-					err,
-				)
+		filename := path.Base(review.Diff.FilePathNew) + ".md"
 
-				continue
-			}
+		err := saveReviewToFile(filename, review.Review)
+		if err != nil {
+			fmt.Printf("⚠️ couldn't save the review for %s:  %s\n",
+				filename,
+				err,
+			)
 
-			fmt.Printf("💾 Saved review to %s\n", filename)
+			continue
 		}
 
-		fmt.Println("Done! 🏁")
-		return nil
-	}))
+		fmt.Printf("💾 Saved review to %s\n", filename)
+	}
 }
 
 func getCodeReviews(diffs []*gh.GitDiff, model, apiKey string, svc CompletionServiceInterface) ([]ReviewedDiff, error) {
@@ -157,7 +168,7 @@ func saveReviewToFile(filename, reviewContent string) error {
 	}
 
 	// Write the review content to the file
-	err := os.WriteFile(filename, []byte(reviewContent), 0644)
+	err := os.WriteFile(filename, []byte(reviewContent), DefaultFilePerms)
 	if err != nil {
 		return fmt.Errorf("failed to write review to file: %s", err)
 	}
@@ -180,6 +191,11 @@ func coalesceConfiguration(cliArgs *argT) (*argT, error) {
 		cliArgs.ApiKey = envArgs.ApiKey
 	}
 
+	// If no model is provided, use the default model
+	if cliArgs.CompletionModel == "" {
+		cliArgs.CompletionModel = DefaultOpenAIModel
+	}
+
 	return cliArgs, nil
 }
 
diff --git a/main_test.go b/main_test.go
index dddbc36..9f6d93d 100644
--- a/main_test.go
+++ b/main_test.go
@@ -24,6 +24,21 @@ func TestCoalesceConfiguration_Key_CLIOverride(t *testing.T) {
 	assert.Equal(t, "overridden_key", result.ApiKey)
 }
 
+func TestCoalesceConfiguration_Model_CLIOverride(t *testing.T) {
+	// Set up to restore the value later
+	currentEnvVar := os.Getenv("CADRE_AI_MODEL")
+	defer os.Setenv("CADRE_AI_MODEL", currentEnvVar)
+
+	// Set up an override
+	err := os.Setenv("CADRE_AI_MODEL", "gpt-4")
+	require.NoError(t, err)
+
+	args := &argT{CompletionModel: "overridden_key"}
+	result, _ := coalesceConfiguration(args)
+
+	assert.Equal(t, "overridden_key", result.ApiKey)
+}
+
 func TestProcessPullRequest(t *testing.T) {
 	// Create a mock GitHub client
 	mockClient := &MockGithubClient{}