diff --git a/CHANGELOG.md b/CHANGELOG.md
index 5cbd9e29bf..7eb5cfe757 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -21,6 +21,20 @@
 
     The above code will be considered valid starting with this release. This change to esbuild follows a [similar change to TypeScript](https://github.com/microsoft/TypeScript/pull/60225) which will allow this syntax starting with TypeScript 5.7.
 
+* Allow quoted property names in `--define` and `--pure` ([#4008](https://github.com/evanw/esbuild/issues/4008))
+
+    The `define` and `pure` API options now accept identifier expressions containing quoted property names. Previously all identifiers in the identifier expression had to be bare identifiers. This change now makes `--define` and `--pure` consistent with `--global-name`, which already supported quoted property names. For example, the following is now possible:
+
+    ```js
+    // The following code now transforms to "return true;\n"
+    console.log(esbuild.transformSync(
+      `return process.env['SOME-TEST-VAR']`,
+      { define: { 'process.env["SOME-TEST-VAR"]': 'true' } },
+    ))
+    ```
+
+    Note that if you're passing values like this on the command line using esbuild's `--define` flag, then you'll need to know how to escape quote characters for your shell. You may find esbuild's JavaScript API more ergonomic and portable than writing shell code.
+
 * Minify empty `try`/`catch`/`finally` blocks ([#4003](https://github.com/evanw/esbuild/issues/4003))
 
     With this release, esbuild will now attempt to minify empty `try` blocks:
diff --git a/pkg/api/api_impl.go b/pkg/api/api_impl.go
index 69757d2cc3..d294d366b9 100644
--- a/pkg/api/api_impl.go
+++ b/pkg/api/api_impl.go
@@ -386,11 +386,11 @@ func validateSupported(log logger.Log, supported map[string]bool) (
 	return
 }
 
-func validateGlobalName(log logger.Log, text string) []string {
+func validateGlobalName(log logger.Log, text string, path string) []string {
 	if text != "" {
 		source := logger.Source{
-			KeyPath:    logger.Path{Text: "(global path)"},
-			PrettyPath: "(global name)",
+			KeyPath:    logger.Path{Text: path},
+			PrettyPath: path,
 			Contents:   text,
 		}
 
@@ -560,20 +560,11 @@ func validateDefines(
 
 	for _, key := range sortedKeys {
 		value := defines[key]
-		keyParts := strings.Split(key, ".")
-		mapKey := mapKeyForDefine(keyParts)
-
-		// The key must be a dot-separated identifier list
-		for _, part := range keyParts {
-			if !js_ast.IsIdentifier(part) {
-				if part == key {
-					log.AddError(nil, logger.Range{}, fmt.Sprintf("The define key %q must be a valid identifier", key))
-				} else {
-					log.AddError(nil, logger.Range{}, fmt.Sprintf("The define key %q contains invalid identifier %q", key, part))
-				}
-				continue
-			}
+		keyParts := validateGlobalName(log, key, "(define name)")
+		if keyParts == nil {
+			continue
 		}
+		mapKey := mapKeyForDefine(keyParts)
 
 		// Parse the value
 		defineExpr, injectExpr := js_parser.ParseDefineExprOrJSON(value)
@@ -678,16 +669,11 @@ func validateDefines(
 	}
 
 	for _, key := range pureFns {
-		keyParts := strings.Split(key, ".")
-		mapKey := mapKeyForDefine(keyParts)
-
-		// The key must be a dot-separated identifier list
-		for _, part := range keyParts {
-			if !js_ast.IsIdentifier(part) {
-				log.AddError(nil, logger.Range{}, fmt.Sprintf("Invalid pure function: %q", key))
-				continue
-			}
+		keyParts := validateGlobalName(log, key, "(pure name)")
+		if keyParts == nil {
+			continue
 		}
+		mapKey := mapKeyForDefine(keyParts)
 
 		// Merge with any previously-specified defines
 		define := rawDefines[mapKey]
@@ -1285,7 +1271,7 @@ func validateBuildOptions(
 		ASCIIOnly:             validateASCIIOnly(buildOpts.Charset),
 		IgnoreDCEAnnotations:  buildOpts.IgnoreAnnotations,
 		TreeShaking:           validateTreeShaking(buildOpts.TreeShaking, buildOpts.Bundle, buildOpts.Format),
-		GlobalName:            validateGlobalName(log, buildOpts.GlobalName),
+		GlobalName:            validateGlobalName(log, buildOpts.GlobalName, "(global name)"),
 		CodeSplitting:         buildOpts.Splitting,
 		OutputFormat:          validateFormat(buildOpts.Format),
 		AbsOutputFile:         validatePath(log, realFS, buildOpts.Outfile, "outfile path"),
@@ -1729,7 +1715,7 @@ func transformImpl(input string, transformOpts TransformOptions) TransformResult
 		SourceRoot:            transformOpts.SourceRoot,
 		ExcludeSourcesContent: transformOpts.SourcesContent == SourcesContentExclude,
 		OutputFormat:          validateFormat(transformOpts.Format),
-		GlobalName:            validateGlobalName(log, transformOpts.GlobalName),
+		GlobalName:            validateGlobalName(log, transformOpts.GlobalName, "(global name)"),
 		MinifySyntax:          transformOpts.MinifySyntax,
 		MinifyWhitespace:      transformOpts.MinifyWhitespace,
 		MinifyIdentifiers:     transformOpts.MinifyIdentifiers,
diff --git a/scripts/js-api-tests.js b/scripts/js-api-tests.js
index 534375a181..d9d6fea7a0 100644
--- a/scripts/js-api-tests.js
+++ b/scripts/js-api-tests.js
@@ -6088,7 +6088,7 @@ class Foo {
     assert.strictEqual(code, `if (x) ;\n`)
   },
 
-  async define({ esbuild }) {
+  async defineProcessEnvNodeEnv({ esbuild }) {
     const define = { 'process.env.NODE_ENV': '"something"' }
 
     const { code: code1 } = await esbuild.transform(`console.log(process.env.NODE_ENV)`, { define })
@@ -6165,6 +6165,32 @@ class Foo {
 `)
   },
 
+  async defineQuotedPropertyNameTransform({ esbuild }) {
+    const { code: code1 } = await esbuild.transform(`return x.y['z']`, { define: { 'x.y["z"]': 'true' } })
+    assert.strictEqual(code1, `return true;\n`)
+
+    const { code: code2 } = await esbuild.transform(`foo(x['y'].z, x.y['z'], x['y']['z'])`, { define: { 'x.y.z': 'true' } })
+    assert.strictEqual(code2, `foo(true, true, true);\n`)
+
+    const { code: code3 } = await esbuild.transform(`foo(x['y'].z, x.y['z'], x['y']['z'])`, { define: { 'x["y"].z': 'true' } })
+    assert.strictEqual(code3, `foo(true, true, true);\n`)
+
+    const { code: code4 } = await esbuild.transform(`foo(x['y'].z, x.y['z'], x['y']['z'])`, { define: { 'x.y["z"]': 'true' } })
+    assert.strictEqual(code4, `foo(true, true, true);\n`)
+
+    const { code: code5 } = await esbuild.transform(`foo(x['y'].z, x.y['z'], x['y']['z'])`, { define: { 'x["y"][\'z\']': 'true' } })
+    assert.strictEqual(code5, `foo(true, true, true);\n`)
+  },
+
+  async defineQuotedPropertyNameBuild({ esbuild }) {
+    const { outputFiles } = await esbuild.build({
+      stdin: { contents: `return process.env['SOME-TEST-VAR']` },
+      define: { 'process.env["SOME-TEST-VAR"]': 'true' },
+      write: false,
+    })
+    assert.strictEqual(outputFiles[0].text, `return true;\n`)
+  },
+
   async json({ esbuild }) {
     const { code } = await esbuild.transform(`{ "x": "y" }`, { loader: 'json' })
     assert.strictEqual(code, `module.exports = { x: "y" };\n`)