diff --git a/spring-web/src/main/java/org/springframework/web/util/RfcUriParser.java b/spring-web/src/main/java/org/springframework/web/util/RfcUriParser.java
index 3198e93590a..b7c4e824200 100644
--- a/spring-web/src/main/java/org/springframework/web/util/RfcUriParser.java
+++ b/spring-web/src/main/java/org/springframework/web/util/RfcUriParser.java
@@ -24,6 +24,7 @@ import org.jspecify.annotations.Nullable;
 
 import org.springframework.core.log.LogDelegateFactory;
 import org.springframework.util.Assert;
+import org.springframework.util.StringUtils;
 
 /**
  * Parser for URIs based on RFC 3986 syntax.
@@ -545,7 +546,8 @@ abstract class RfcUriParser {
 
 		public InternalParser capturePort() {
 			verify(this.openCurlyBracketCount == 0, this, "Bad authority");
-			this.port = captureComponent("port");
+			String value = captureComponent("port");
+			this.port = (StringUtils.hasText(value) ? value : null);
 			return this;
 		}
 
diff --git a/spring-web/src/main/java/org/springframework/web/util/UriBuilder.java b/spring-web/src/main/java/org/springframework/web/util/UriBuilder.java
index 4b033027bbb..14d61406fa4 100644
--- a/spring-web/src/main/java/org/springframework/web/util/UriBuilder.java
+++ b/spring-web/src/main/java/org/springframework/web/util/UriBuilder.java
@@ -73,7 +73,7 @@ public interface UriBuilder {
 	/**
 	 * Set the URI port. Use this method only when the port needs to be
 	 * parameterized with a URI variable. Otherwise use {@link #port(int)}.
-	 * Passing {@code null} will clear the port of this builder.
+	 * Passing {@code null} or an empty String will clear the port of this builder.
 	 * @param port the URI port
 	 */
 	UriBuilder port(@Nullable String port);
diff --git a/spring-web/src/main/java/org/springframework/web/util/UriComponentsBuilder.java b/spring-web/src/main/java/org/springframework/web/util/UriComponentsBuilder.java
index 62eae9fe2bf..a454d3a2cd1 100644
--- a/spring-web/src/main/java/org/springframework/web/util/UriComponentsBuilder.java
+++ b/spring-web/src/main/java/org/springframework/web/util/UriComponentsBuilder.java
@@ -513,7 +513,7 @@ public class UriComponentsBuilder implements UriBuilder, Cloneable {
 
 	@Override
 	public UriComponentsBuilder port(@Nullable String port) {
-		this.port = port;
+		this.port = (StringUtils.hasText(port) ? port : null);
 		if (port != null) {
 			resetSchemeSpecificPart();
 		}
diff --git a/spring-web/src/test/java/org/springframework/web/util/UriComponentsBuilderTests.java b/spring-web/src/test/java/org/springframework/web/util/UriComponentsBuilderTests.java
index fc0a40a54c3..9222ca41812 100644
--- a/spring-web/src/test/java/org/springframework/web/util/UriComponentsBuilderTests.java
+++ b/spring-web/src/test/java/org/springframework/web/util/UriComponentsBuilderTests.java
@@ -937,11 +937,17 @@ class UriComponentsBuilderTests {
 	@ParameterizedTest
 	@EnumSource
 	void verifyInvalidPort(ParserType parserType) {
-		String url = "http://localhost:XXX/path";
-		assertThatIllegalArgumentException()
-				.isThrownBy(() -> UriComponentsBuilder.fromUriString(url, parserType).build().toUri());
-		assertThatIllegalArgumentException()
-				.isThrownBy(() -> UriComponentsBuilder.fromUriString(url, parserType).build().toUri());
+		assertThatIllegalArgumentException().isThrownBy(() ->
+				UriComponentsBuilder.fromUriString("http://localhost:XXX/path", parserType).build().toUri());
+	}
+
+	@ParameterizedTest // gh-37117
+	@EnumSource
+	void verifyEmptyPort(ParserType parserType) {
+		URI uri = UriComponentsBuilder.fromUriString("http://localhost:/path", parserType).build().toUri();
+		assertThat(uri.getHost()).isEqualTo("localhost");
+		assertThat(uri.getPort()).isEqualTo(-1);
+		assertThat(uri.getPath()).isEqualTo("/path");
 	}
 
 	@ParameterizedTest // gh-27039
diff --git a/spring-web/src/test/java/org/springframework/web/util/UriComponentsTests.java b/spring-web/src/test/java/org/springframework/web/util/UriComponentsTests.java
index ffa6a975d22..43a03ef6e11 100644
--- a/spring-web/src/test/java/org/springframework/web/util/UriComponentsTests.java
+++ b/spring-web/src/test/java/org/springframework/web/util/UriComponentsTests.java
@@ -201,10 +201,9 @@ class UriComponentsTests {
 				.isThrownBy(() -> fromUriString("https://example.com:XXX/bar", parserType));
 	}
 
-	@ParameterizedTest
-	@EnumSource
-	void invalidPortSet(ParserType parserType) {
-		UriComponents uriComponents = fromUriString("https://example.com/bar", parserType).port("XXX").build();
+	@Test
+	void invalidPortSet() {
+		UriComponents uriComponents = fromUriString("https://example.com/bar").port("XXX").build();
 
 		assertThatIllegalStateException()
 			.isThrownBy(uriComponents::getPort)
@@ -215,6 +214,12 @@ class UriComponentsTests {
 			.withMessage("The port must be an integer: XXX");
 	}
 
+	@Test // gh-37117
+	void emptyPortSet() {
+		UriComponents uriComponents = fromUriString("https://example.com/bar").port("").build();
+		assertThat(uriComponents.getPort()).isEqualTo(-1);
+	}
+
 	@Test
 	void expandEncoded() {
 		assertThatIllegalStateException().isThrownBy(() ->