diff --git a/CHANGELOG.md b/CHANGELOG.md
index a5ed5d1a..534103f6 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -36,6 +36,9 @@ All notable changes to this project will be documented in this file, in reverse
 - [#51](https://github.com/webimpress/coding-standard/pull/51) adds check for blank lines and comments before arrow in arrays in `Array\Format` sniff.
   Arrow must be after the index value, can be in new line, but any additional lines or comments are disallowed. 
 
+- [#54](https://github.com/webimpress/coding-standard/pull/54) adds `Namespaces\UniqueImport` sniff to detect if class/function/constant is imported only once.
+  Sniff checks also if the name is used only once. The same name can be used for class/function/constant, and constant names are case sensitive.
+
 ### Changed
 
 - [#42](https://github.com/webimpress/coding-standard/pull/42) changes `NamingConventions\ValidVariableName` to require variable names be in strict camelCase. It means two capital letters next to each other are not allowed.
diff --git a/src/WebimpressCodingStandard/Sniffs/Namespaces/UniqueImportSniff.php b/src/WebimpressCodingStandard/Sniffs/Namespaces/UniqueImportSniff.php
new file mode 100644
index 00000000..23eaae44
--- /dev/null
+++ b/src/WebimpressCodingStandard/Sniffs/Namespaces/UniqueImportSniff.php
@@ -0,0 +1,168 @@
+<?php
+
+declare(strict_types=1);
+
+namespace WebimpressCodingStandard\Sniffs\Namespaces;
+
+use PHP_CodeSniffer\Files\File;
+use PHP_CodeSniffer\Sniffs\Sniff;
+use PHP_CodeSniffer\Util\Tokens;
+use WebimpressCodingStandard\CodingStandard;
+
+use function explode;
+use function in_array;
+use function max;
+use function strtolower;
+
+use const T_AS;
+use const T_COMMA;
+use const T_NAMESPACE;
+use const T_NS_SEPARATOR;
+use const T_OPEN_TAG;
+use const T_OPEN_USE_GROUP;
+use const T_SEMICOLON;
+use const T_STRING;
+use const T_USE;
+
+class UniqueImportSniff implements Sniff
+{
+    /**
+     * @return int[]
+     */
+    public function register() : array
+    {
+        return [T_OPEN_TAG, T_NAMESPACE];
+    }
+
+    /**
+     * @param int $stackPtr
+     */
+    public function process(File $phpcsFile, $stackPtr) : int
+    {
+        $tokens = $phpcsFile->getTokens();
+
+        if ($tokens[$stackPtr]['code'] === T_OPEN_TAG) {
+            $namespace = $phpcsFile->findNext(T_NAMESPACE, $stackPtr + 1);
+            if ($namespace) {
+                return $namespace;
+            }
+        }
+
+        $uses = $this->getUseStatements($phpcsFile, $stackPtr);
+
+        foreach ($uses as $type => $data) {
+            foreach ($data as $name => $ptrs) {
+                if (isset($ptrs[1])) {
+                    $ptr = max($ptrs);
+                    if ($type === 'full') {
+                        $error = 'The same %s %s is already imported';
+                        $data = [explode('::', $name)[0], $tokens[$ptr]['content']];
+                        $phpcsFile->addError($error, $ptr, 'DuplicateImport', $data);
+                    } else {
+                        $error = 'The name %s is already used for another %s';
+                        $data = [$tokens[$ptr]['content'], $type];
+                        $phpcsFile->addError($error, $ptr, 'DuplicateAlias', $data);
+                    }
+                }
+            }
+        }
+
+        return $tokens[$stackPtr]['code'] === T_OPEN_TAG
+            ? $phpcsFile->numTokens + 1
+            : $stackPtr + 1;
+    }
+
+    /**
+     * @return string[][]
+     */
+    private function getUseStatements(File $phpcsFile, int $scopePtr) : array
+    {
+        $tokens = $phpcsFile->getTokens();
+
+        $uses = [];
+
+        if (isset($tokens[$scopePtr]['scope_opener'])) {
+            $start = $tokens[$scopePtr]['scope_opener'];
+            $end = $tokens[$scopePtr]['scope_closer'];
+        } else {
+            $start = $scopePtr;
+            $end = null;
+        }
+
+        while ($use = $phpcsFile->findNext(T_USE, $start + 1, $end)) {
+            if (! CodingStandard::isGlobalUse($phpcsFile, $use)) {
+                $start = $use;
+                continue;
+            }
+
+            $semicolon = $phpcsFile->findNext(T_SEMICOLON, $use + 1);
+
+            $type = 'class';
+            $next = $phpcsFile->findNext(Tokens::$emptyTokens, $use + 1, null, true);
+            if ($tokens[$next]['code'] === T_STRING
+                && in_array(strtolower($tokens[$next]['content']), ['const', 'function'], true)
+            ) {
+                $type = strtolower($tokens[$next]['content']);
+
+                $use = $next + 1;
+            }
+
+            $current = $semicolon;
+            while ($namePtr = $phpcsFile->findPrevious(T_STRING, $current, $use)) {
+                $key = $tokens[$namePtr]['content'];
+                if ($type !== 'const') {
+                    $key = strtolower($key);
+                }
+                $uses[$type][$key][] = $namePtr;
+
+                $lastPtr = $namePtr;
+                $as = $phpcsFile->findPrevious(Tokens::$emptyTokens, $namePtr - 1, null, true);
+                if ($tokens[$as]['code'] === T_AS) {
+                    $lastPtr = $phpcsFile->findPrevious(T_STRING, $as - 1);
+                    $key = $tokens[$lastPtr]['content'];
+                    if ($type !== 'const') {
+                        $key = strtolower($key);
+                    }
+                }
+
+                $from = $phpcsFile->findPrevious(
+                    Tokens::$emptyTokens + [
+                        T_STRING => T_STRING,
+                        T_NS_SEPARATOR => T_NS_SEPARATOR,
+                    ],
+                    $lastPtr - 1,
+                    $use,
+                    true
+                ) ?: $use;
+
+                $full = '';
+                for ($i = $from + 1; $i < $lastPtr; ++$i) {
+                    if ($tokens[$i]['code'] === T_STRING || $tokens[$i]['code'] === T_NS_SEPARATOR) {
+                        $full .= $tokens[$i]['content'];
+                    }
+                }
+                $full .= $key;
+
+                $prev = $phpcsFile->findPrevious(T_OPEN_USE_GROUP, $lastPtr - 1, $use);
+                if ($prev) {
+                    for ($i = $prev - 1; $i > $use; --$i) {
+                        if ($tokens[$i]['code'] === T_STRING || $tokens[$i]['code'] === T_NS_SEPARATOR) {
+                            $full = $tokens[$i]['content'] . $full;
+                        }
+                    }
+                }
+
+                $uses['full'][$type . '::' . $full][] = $lastPtr;
+
+                $current = $phpcsFile->findPrevious(T_COMMA, $namePtr - 1, $use);
+                if ($current === false) {
+                    break;
+                }
+            }
+
+            $start = $semicolon;
+        }
+
+        return $uses;
+    }
+}
diff --git a/test/Sniffs/Namespaces/UniqueImportUnitTest.1.inc b/test/Sniffs/Namespaces/UniqueImportUnitTest.1.inc
new file mode 100644
index 00000000..f37df0fa
--- /dev/null
+++ b/test/Sniffs/Namespaces/UniqueImportUnitTest.1.inc
@@ -0,0 +1,37 @@
+<?php
+
+namespace OneNamespace;
+
+use MyNamespace\MyClass;
+use MyNamespace\General;
+use OtherNamespace\MyClass as General;
+
+use function MyFunctions\general;
+use function array_merge as f1;
+use function array_diff as f1;
+use function array_diff as f2;
+use function
+    array_filter,
+    array_merge;
+
+use const MyConsts\GENERAL;
+use const MyConsts\OTHER as A;
+use const MyConsts\FOO as A;
+use const Other\{
+    CONST1,
+    CONST2 as General,
+    CONST3 as GENERAL
+};
+use const Myconsts\OTHER;
+
+class One
+{
+    use MyTrait;
+
+    private $closure;
+
+    public function __construct(MyClass $a)
+    {
+        $this->closure = function() use($a) {};
+    }
+}
diff --git a/test/Sniffs/Namespaces/UniqueImportUnitTest.2.inc b/test/Sniffs/Namespaces/UniqueImportUnitTest.2.inc
new file mode 100644
index 00000000..c4776f6f
--- /dev/null
+++ b/test/Sniffs/Namespaces/UniqueImportUnitTest.2.inc
@@ -0,0 +1,43 @@
+<?php
+
+namespace First {
+    use MyNamespace\MyClass;
+    use MyNamespace\General;
+    use OtherNamespace\MyClass as General;
+
+    use function MyFunctions\general;
+    use function array_merge as f1;
+    use function array_diff as f1;
+    use function array_diff as f2;
+    use function
+        array_filter,
+        array_merge;
+
+    use const MyConsts\GENERAL;
+    use const MyConsts\OTHER as A;
+    use const MyConsts\FOO as A;
+    use const Other\{
+        CONST1,
+        CONST2 as General,
+        CONST3 as GENERAL
+    };
+    use const Myconsts\OTHER;
+}
+
+namespace Second {
+    use MyNamespace\MyClass;
+
+    use function array_merge;
+
+    use const A;
+
+    class Two {
+        use MyTrait;
+
+        private $closure;
+
+        public function __construct(MyClass $a) {
+            $this->closure = function() use($a) {};
+        }
+    }
+}
diff --git a/test/Sniffs/Namespaces/UniqueImportUnitTest.inc b/test/Sniffs/Namespaces/UniqueImportUnitTest.inc
new file mode 100644
index 00000000..3e41f6d8
--- /dev/null
+++ b/test/Sniffs/Namespaces/UniqueImportUnitTest.inc
@@ -0,0 +1,33 @@
+<?php
+
+use MyNamespace\MyClass;
+use MyNamespace\General;
+use OtherNamespace\MyClass as General;
+
+use function MyFunctions\general;
+use function array_merge as f1;
+use function array_diff as f1;
+use function array_diff as f2;
+use function
+    array_filter,
+    array_merge;
+
+use const MyConsts\GENERAL;
+use const MyConsts\OTHER as A;
+use const MyConsts\FOO as A;
+use const Other\{
+    CONST1,
+    CONST2 as General,
+    CONST3 as GENERAL
+};
+use const Myconsts\OTHER;
+
+class None {
+    use MyTrait;
+
+    private $closure;
+
+    public function __construct(MyClass $a) {
+        $this->closure = function() use($a) {};
+    }
+}
diff --git a/test/Sniffs/Namespaces/UniqueImportUnitTest.php b/test/Sniffs/Namespaces/UniqueImportUnitTest.php
new file mode 100644
index 00000000..a753639c
--- /dev/null
+++ b/test/Sniffs/Namespaces/UniqueImportUnitTest.php
@@ -0,0 +1,48 @@
+<?php
+
+declare(strict_types=1);
+
+namespace WebimpressCodingStandardTest\Sniffs\Namespaces;
+
+use WebimpressCodingStandardTest\Sniffs\AbstractTestCase;
+
+class UniqueImportUnitTest extends AbstractTestCase
+{
+    protected function getErrorList(string $testFile = '') : array
+    {
+        switch ($testFile) {
+            case 'UniqueImportUnitTest.1.inc':
+                return [
+                    7 => 1,
+                    11 => 1,
+                    12 => 1,
+                    15 => 1,
+                    19 => 1,
+                    23 => 1,
+                ];
+            case 'UniqueImportUnitTest.2.inc':
+                return [
+                    6 => 1,
+                    10 => 1,
+                    11 => 1,
+                    14 => 1,
+                    18 => 1,
+                    22 => 1,
+                ];
+        }
+
+        return [
+            5 => 1,
+            9 => 1,
+            10 => 1,
+            13 => 1,
+            17 => 1,
+            21 => 1,
+        ];
+    }
+
+    protected function getWarningList(string $testFile = '') : array
+    {
+        return [];
+    }
+}