diff --git a/packages/kbn-esql-validation-autocomplete/src/autocomplete/autocomplete.test.ts b/packages/kbn-esql-validation-autocomplete/src/autocomplete/autocomplete.test.ts
index 809552f02b999..4be855868d39b 100644
--- a/packages/kbn-esql-validation-autocomplete/src/autocomplete/autocomplete.test.ts
+++ b/packages/kbn-esql-validation-autocomplete/src/autocomplete/autocomplete.test.ts
@@ -559,7 +559,10 @@ describe('autocomplete', () => {
   }
 
   describe('sort', () => {
-    testSuggestions('from a | sort ', getFieldNamesByType('any'));
+    testSuggestions('from a | sort ', [
+      ...getFieldNamesByType('any'),
+      ...getFunctionSignaturesByReturnType('sort', 'any', { evalMath: true }),
+    ]);
     testSuggestions('from a | sort stringField ', ['asc', 'desc', ',', '|']);
     testSuggestions('from a | sort stringField desc ', ['nulls first', 'nulls last', ',', '|']);
     // @TODO: improve here
diff --git a/packages/kbn-esql-validation-autocomplete/src/autocomplete/autocomplete.ts b/packages/kbn-esql-validation-autocomplete/src/autocomplete/autocomplete.ts
index 6c25afe41f848..71494b64cf790 100644
--- a/packages/kbn-esql-validation-autocomplete/src/autocomplete/autocomplete.ts
+++ b/packages/kbn-esql-validation-autocomplete/src/autocomplete/autocomplete.ts
@@ -594,7 +594,11 @@ async function getExpressionSuggestionsByType(
             option?.name,
             getFieldsByType,
             {
-              functions: canHaveAssignments,
+              // TODO instead of relying on canHaveAssignments and other command name checks
+              // we should have a more generic way to determine if a command can have functions.
+              // I think it comes down to the definition of 'column' since 'any' should always
+              // include functions.
+              functions: canHaveAssignments || command.name === 'sort',
               fields: !argDef.constantOnly,
               variables: anyVariables,
               literals: argDef.constantOnly,
diff --git a/packages/kbn-esql-validation-autocomplete/src/definitions/builtin.ts b/packages/kbn-esql-validation-autocomplete/src/definitions/builtin.ts
index 805bec79b03e4..20adda63602df 100644
--- a/packages/kbn-esql-validation-autocomplete/src/definitions/builtin.ts
+++ b/packages/kbn-esql-validation-autocomplete/src/definitions/builtin.ts
@@ -19,7 +19,7 @@ function createMathDefinition(
     type: 'builtin',
     name,
     description,
-    supportedCommands: ['eval', 'where', 'row', 'stats'],
+    supportedCommands: ['eval', 'where', 'row', 'stats', 'sort'],
     supportedOptions: ['by'],
     signatures: types.map((type) => {
       if (Array.isArray(type)) {
@@ -59,7 +59,7 @@ function createComparisonDefinition(
     type: 'builtin' as const,
     name,
     description,
-    supportedCommands: ['eval', 'where', 'row'],
+    supportedCommands: ['eval', 'where', 'row', 'sort'],
     supportedOptions: ['by'],
     validate,
     signatures: [
@@ -296,7 +296,7 @@ export const builtinFunctions: FunctionDefinition[] = [
     ignoreAsSuggestion: /not/.test(name),
     name,
     description,
-    supportedCommands: ['eval', 'where', 'row'],
+    supportedCommands: ['eval', 'where', 'row', 'sort'],
     supportedOptions: ['by'],
     signatures: [
       {
@@ -322,7 +322,7 @@ export const builtinFunctions: FunctionDefinition[] = [
     ignoreAsSuggestion: /not/.test(name),
     name,
     description,
-    supportedCommands: ['eval', 'where', 'row'],
+    supportedCommands: ['eval', 'where', 'row', 'sort'],
     signatures: [
       {
         params: [
@@ -371,7 +371,7 @@ export const builtinFunctions: FunctionDefinition[] = [
     type: 'builtin' as const,
     name,
     description,
-    supportedCommands: ['eval', 'where', 'row'],
+    supportedCommands: ['eval', 'where', 'row', 'sort'],
     supportedOptions: ['by'],
     signatures: [
       {
@@ -410,7 +410,7 @@ export const builtinFunctions: FunctionDefinition[] = [
     description: i18n.translate('kbn-esql-validation-autocomplete.esql.definition.notDoc', {
       defaultMessage: 'Not',
     }),
-    supportedCommands: ['eval', 'where', 'row'],
+    supportedCommands: ['eval', 'where', 'row', 'sort'],
     supportedOptions: ['by'],
     signatures: [
       {
@@ -436,7 +436,7 @@ export const builtinFunctions: FunctionDefinition[] = [
     type: 'builtin',
     name,
     description,
-    supportedCommands: ['eval', 'where', 'row'],
+    supportedCommands: ['eval', 'where', 'row', 'sort'],
     signatures: [
       {
         params: [{ name: 'left', type: 'any' }],
diff --git a/packages/kbn-esql-validation-autocomplete/src/definitions/commands.ts b/packages/kbn-esql-validation-autocomplete/src/definitions/commands.ts
index 84e85c4d6e797..861d18110d08f 100644
--- a/packages/kbn-esql-validation-autocomplete/src/definitions/commands.ts
+++ b/packages/kbn-esql-validation-autocomplete/src/definitions/commands.ts
@@ -330,13 +330,14 @@ export const commandDefinitions: CommandDefinition[] = [
       '… | sort a desc, b nulls last, c asc nulls first',
       '… | sort b nulls last',
       '… | sort c asc nulls first',
+      '… | sort a - abs(b)',
     ],
     options: [],
     modes: [],
     signature: {
       multipleParams: true,
       params: [
-        { name: 'column', type: 'column' },
+        { name: 'expression', type: 'any' },
         { name: 'direction', type: 'string', optional: true, values: ['asc', 'desc'] },
         { name: 'nulls', type: 'string', optional: true, values: ['nulls first', 'nulls last'] },
       ],
diff --git a/packages/kbn-esql-validation-autocomplete/src/definitions/functions.ts b/packages/kbn-esql-validation-autocomplete/src/definitions/functions.ts
index 57dcb9acf93b1..d0b9110252b49 100644
--- a/packages/kbn-esql-validation-autocomplete/src/definitions/functions.ts
+++ b/packages/kbn-esql-validation-autocomplete/src/definitions/functions.ts
@@ -1692,7 +1692,7 @@ export const evalFunctionsDefinitions: FunctionDefinition[] = [
   .sort(({ name: a }, { name: b }) => a.localeCompare(b))
   .map((def) => ({
     ...def,
-    supportedCommands: ['stats', 'eval', 'where', 'row'],
+    supportedCommands: ['stats', 'eval', 'where', 'row', 'sort'],
     supportedOptions: ['by'],
     type: 'eval',
   }));
diff --git a/packages/kbn-esql-validation-autocomplete/src/validation/esql_validation_meta_tests.json b/packages/kbn-esql-validation-autocomplete/src/validation/esql_validation_meta_tests.json
index bbe3903c1aa07..6b8c666dd6b5b 100644
--- a/packages/kbn-esql-validation-autocomplete/src/validation/esql_validation_meta_tests.json
+++ b/packages/kbn-esql-validation-autocomplete/src/validation/esql_validation_meta_tests.json
@@ -16092,6 +16092,509 @@
       "error": [],
       "warning": []
     },
+    {
+      "query": "from a_index | sort abs(numberField) - to_long(stringField) desc nulls first",
+      "error": [],
+      "warning": []
+    },
+    {
+      "query": "from a_index | sort avg(numberField)",
+      "error": [
+        "SORT does not support function avg"
+      ],
+      "warning": []
+    },
+    {
+      "query": "from a_index | sort sum(numberField)",
+      "error": [
+        "SORT does not support function sum"
+      ],
+      "warning": []
+    },
+    {
+      "query": "from a_index | sort median(numberField)",
+      "error": [
+        "SORT does not support function median"
+      ],
+      "warning": []
+    },
+    {
+      "query": "from a_index | sort median_absolute_deviation(numberField)",
+      "error": [
+        "SORT does not support function median_absolute_deviation"
+      ],
+      "warning": []
+    },
+    {
+      "query": "from a_index | sort percentile(numberField, 5)",
+      "error": [
+        "SORT does not support function percentile"
+      ],
+      "warning": []
+    },
+    {
+      "query": "from a_index | sort max(numberField)",
+      "error": [
+        "SORT does not support function max"
+      ],
+      "warning": []
+    },
+    {
+      "query": "from a_index | sort min(numberField)",
+      "error": [
+        "SORT does not support function min"
+      ],
+      "warning": []
+    },
+    {
+      "query": "from a_index | sort count(stringField)",
+      "error": [
+        "SORT does not support function count"
+      ],
+      "warning": []
+    },
+    {
+      "query": "from a_index | sort count_distinct(stringField, numberField)",
+      "error": [
+        "SORT does not support function count_distinct"
+      ],
+      "warning": []
+    },
+    {
+      "query": "from a_index | sort st_centroid_agg(cartesianPointField)",
+      "error": [
+        "SORT does not support function st_centroid_agg"
+      ],
+      "warning": []
+    },
+    {
+      "query": "from a_index | sort values(stringField)",
+      "error": [
+        "SORT does not support function values"
+      ],
+      "warning": []
+    },
+    {
+      "query": "from a_index | sort bucket(dateField, 1 year)",
+      "error": [
+        "SORT does not support function bucket"
+      ],
+      "warning": []
+    },
+    {
+      "query": "from a_index | sort abs(numberField)",
+      "error": [],
+      "warning": []
+    },
+    {
+      "query": "from a_index | sort acos(numberField)",
+      "error": [],
+      "warning": []
+    },
+    {
+      "query": "from a_index | sort asin(numberField)",
+      "error": [],
+      "warning": []
+    },
+    {
+      "query": "from a_index | sort atan(numberField)",
+      "error": [],
+      "warning": []
+    },
+    {
+      "query": "from a_index | sort atan2(numberField, numberField)",
+      "error": [],
+      "warning": []
+    },
+    {
+      "query": "from a_index | sort case(booleanField, stringField)",
+      "error": [],
+      "warning": []
+    },
+    {
+      "query": "from a_index | sort ceil(numberField)",
+      "error": [],
+      "warning": []
+    },
+    {
+      "query": "from a_index | sort cidr_match(ipField, stringField)",
+      "error": [],
+      "warning": []
+    },
+    {
+      "query": "from a_index | sort coalesce(stringField)",
+      "error": [],
+      "warning": []
+    },
+    {
+      "query": "from a_index | sort concat(stringField, stringField)",
+      "error": [],
+      "warning": []
+    },
+    {
+      "query": "from a_index | sort cos(numberField)",
+      "error": [],
+      "warning": []
+    },
+    {
+      "query": "from a_index | sort cosh(numberField)",
+      "error": [],
+      "warning": []
+    },
+    {
+      "query": "from a_index | sort date_extract(\"ALIGNED_DAY_OF_WEEK_IN_MONTH\", dateField)",
+      "error": [],
+      "warning": []
+    },
+    {
+      "query": "from a_index | sort date_format(dateField, stringField)",
+      "error": [],
+      "warning": []
+    },
+    {
+      "query": "from a_index | sort date_parse(stringField, stringField)",
+      "error": [],
+      "warning": []
+    },
+    {
+      "query": "from a_index | sort date_trunc(1 year, dateField)",
+      "error": [],
+      "warning": []
+    },
+    {
+      "query": "from a_index | sort e()",
+      "error": [],
+      "warning": []
+    },
+    {
+      "query": "from a_index | sort ends_with(stringField, stringField)",
+      "error": [],
+      "warning": []
+    },
+    {
+      "query": "from a_index | sort floor(numberField)",
+      "error": [],
+      "warning": []
+    },
+    {
+      "query": "from a_index | sort greatest(stringField)",
+      "error": [],
+      "warning": []
+    },
+    {
+      "query": "from a_index | sort least(stringField)",
+      "error": [],
+      "warning": []
+    },
+    {
+      "query": "from a_index | sort left(stringField, numberField)",
+      "error": [],
+      "warning": []
+    },
+    {
+      "query": "from a_index | sort length(stringField)",
+      "error": [],
+      "warning": []
+    },
+    {
+      "query": "from a_index | sort log(numberField, numberField)",
+      "error": [],
+      "warning": []
+    },
+    {
+      "query": "from a_index | sort log10(numberField)",
+      "error": [],
+      "warning": []
+    },
+    {
+      "query": "from a_index | sort ltrim(stringField)",
+      "error": [],
+      "warning": []
+    },
+    {
+      "query": "from a_index | sort mv_avg(numberField)",
+      "error": [],
+      "warning": []
+    },
+    {
+      "query": "from a_index | sort mv_concat(stringField, stringField)",
+      "error": [],
+      "warning": []
+    },
+    {
+      "query": "from a_index | sort mv_count(stringField)",
+      "error": [],
+      "warning": []
+    },
+    {
+      "query": "from a_index | sort mv_dedupe(stringField)",
+      "error": [],
+      "warning": []
+    },
+    {
+      "query": "from a_index | sort mv_first(stringField)",
+      "error": [],
+      "warning": []
+    },
+    {
+      "query": "from a_index | sort mv_last(stringField)",
+      "error": [],
+      "warning": []
+    },
+    {
+      "query": "from a_index | sort mv_max(stringField)",
+      "error": [],
+      "warning": []
+    },
+    {
+      "query": "from a_index | sort mv_median(numberField)",
+      "error": [],
+      "warning": []
+    },
+    {
+      "query": "from a_index | sort mv_min(stringField)",
+      "error": [],
+      "warning": []
+    },
+    {
+      "query": "from a_index | sort mv_slice(stringField, numberField, numberField)",
+      "error": [],
+      "warning": []
+    },
+    {
+      "query": "from a_index | sort mv_sort(stringField, \"asc\")",
+      "error": [],
+      "warning": []
+    },
+    {
+      "query": "from a_index | sort mv_sum(numberField)",
+      "error": [],
+      "warning": []
+    },
+    {
+      "query": "from a_index | sort mv_zip(stringField, stringField, stringField)",
+      "error": [],
+      "warning": []
+    },
+    {
+      "query": "from a_index | sort now()",
+      "error": [],
+      "warning": []
+    },
+    {
+      "query": "from a_index | sort pi()",
+      "error": [],
+      "warning": []
+    },
+    {
+      "query": "from a_index | sort pow(numberField, numberField)",
+      "error": [],
+      "warning": []
+    },
+    {
+      "query": "from a_index | sort replace(stringField, stringField, stringField)",
+      "error": [],
+      "warning": []
+    },
+    {
+      "query": "from a_index | sort right(stringField, numberField)",
+      "error": [],
+      "warning": []
+    },
+    {
+      "query": "from a_index | sort round(numberField, numberField)",
+      "error": [],
+      "warning": []
+    },
+    {
+      "query": "from a_index | sort rtrim(stringField)",
+      "error": [],
+      "warning": []
+    },
+    {
+      "query": "from a_index | sort signum(numberField)",
+      "error": [],
+      "warning": []
+    },
+    {
+      "query": "from a_index | sort sin(numberField)",
+      "error": [],
+      "warning": []
+    },
+    {
+      "query": "from a_index | sort sinh(numberField)",
+      "error": [],
+      "warning": []
+    },
+    {
+      "query": "from a_index | sort split(stringField, stringField)",
+      "error": [],
+      "warning": []
+    },
+    {
+      "query": "from a_index | sort sqrt(numberField)",
+      "error": [],
+      "warning": []
+    },
+    {
+      "query": "from a_index | sort st_contains(geoPointField, geoPointField)",
+      "error": [],
+      "warning": []
+    },
+    {
+      "query": "from a_index | sort st_disjoint(geoPointField, geoPointField)",
+      "error": [],
+      "warning": []
+    },
+    {
+      "query": "from a_index | sort st_intersects(geoPointField, geoPointField)",
+      "error": [],
+      "warning": []
+    },
+    {
+      "query": "from a_index | sort st_within(geoPointField, geoPointField)",
+      "error": [],
+      "warning": []
+    },
+    {
+      "query": "from a_index | sort st_x(geoPointField)",
+      "error": [],
+      "warning": []
+    },
+    {
+      "query": "from a_index | sort st_y(geoPointField)",
+      "error": [],
+      "warning": []
+    },
+    {
+      "query": "from a_index | sort starts_with(stringField, stringField)",
+      "error": [],
+      "warning": []
+    },
+    {
+      "query": "from a_index | sort substring(stringField, numberField, numberField)",
+      "error": [],
+      "warning": []
+    },
+    {
+      "query": "from a_index | sort tan(numberField)",
+      "error": [],
+      "warning": []
+    },
+    {
+      "query": "from a_index | sort tanh(numberField)",
+      "error": [],
+      "warning": []
+    },
+    {
+      "query": "from a_index | sort tau()",
+      "error": [],
+      "warning": []
+    },
+    {
+      "query": "from a_index | sort to_boolean(stringField)",
+      "error": [],
+      "warning": []
+    },
+    {
+      "query": "from a_index | sort to_cartesianpoint(stringField)",
+      "error": [],
+      "warning": []
+    },
+    {
+      "query": "from a_index | sort to_cartesianshape(stringField)",
+      "error": [],
+      "warning": []
+    },
+    {
+      "query": "from a_index | sort to_datetime(stringField)",
+      "error": [],
+      "warning": []
+    },
+    {
+      "query": "from a_index | sort to_degrees(numberField)",
+      "error": [],
+      "warning": []
+    },
+    {
+      "query": "from a_index | sort to_double(stringField)",
+      "error": [],
+      "warning": []
+    },
+    {
+      "query": "from a_index | sort to_geopoint(stringField)",
+      "error": [],
+      "warning": []
+    },
+    {
+      "query": "from a_index | sort to_geoshape(stringField)",
+      "error": [],
+      "warning": []
+    },
+    {
+      "query": "from a_index | sort to_integer(stringField)",
+      "error": [],
+      "warning": []
+    },
+    {
+      "query": "from a_index | sort to_ip(stringField)",
+      "error": [],
+      "warning": []
+    },
+    {
+      "query": "from a_index | sort to_long(stringField)",
+      "error": [],
+      "warning": []
+    },
+    {
+      "query": "from a_index | sort to_lower(stringField)",
+      "error": [],
+      "warning": []
+    },
+    {
+      "query": "from a_index | sort to_radians(numberField)",
+      "error": [],
+      "warning": []
+    },
+    {
+      "query": "from a_index | sort to_string(stringField)",
+      "error": [],
+      "warning": []
+    },
+    {
+      "query": "from a_index | sort to_unsigned_long(stringField)",
+      "error": [],
+      "warning": []
+    },
+    {
+      "query": "from a_index | sort to_upper(stringField)",
+      "error": [],
+      "warning": []
+    },
+    {
+      "query": "from a_index | sort to_version(stringField)",
+      "error": [],
+      "warning": []
+    },
+    {
+      "query": "from a_index | sort trim(stringField)",
+      "error": [],
+      "warning": []
+    },
+    {
+      "query": "from a_index | sort sin(stringField)",
+      "error": [
+        "Argument of [sin] must be [number], found value [stringField] type [string]"
+      ],
+      "warning": []
+    },
+    {
+      "query": "from a_index | sort numberField + stringField",
+      "error": [
+        "Argument of [+] must be [number], found value [stringField] type [string]"
+      ],
+      "warning": []
+    },
     {
       "query": "from a_index | enrich",
       "error": [
diff --git a/packages/kbn-esql-validation-autocomplete/src/validation/validation.test.ts b/packages/kbn-esql-validation-autocomplete/src/validation/validation.test.ts
index 63abfc9dff036..dc37f5b2fd1ff 100644
--- a/packages/kbn-esql-validation-autocomplete/src/validation/validation.test.ts
+++ b/packages/kbn-esql-validation-autocomplete/src/validation/validation.test.ts
@@ -2455,6 +2455,58 @@ describe('validation logic', () => {
       }
       testErrorsAndWarnings(`row a = 1 | stats COUNT(*) | sort \`COUNT(*)\``, []);
       testErrorsAndWarnings(`ROW a = 1 | STATS couNt(*) | SORT \`couNt(*)\``, []);
+
+      describe('sorting by expressions', () => {
+        // SORT accepts complex expressions
+        testErrorsAndWarnings(
+          'from a_index | sort abs(numberField) - to_long(stringField) desc nulls first',
+          []
+        );
+
+        // SORT doesn't accept agg or grouping functions
+        for (const definition of [
+          ...statsAggregationFunctionDefinitions,
+          ...groupingFunctionDefinitions,
+        ]) {
+          const {
+            name,
+            signatures: [firstSignature],
+          } = definition;
+          const fieldMapping = getFieldMapping(firstSignature.params);
+          const printedInvocation = getFunctionSignatures(
+            { ...definition, signatures: [{ ...firstSignature, params: fieldMapping }] },
+            { withTypes: false }
+          )[0].declaration;
+
+          testErrorsAndWarnings(`from a_index | sort ${printedInvocation}`, [
+            `SORT does not support function ${name}`,
+          ]);
+        }
+
+        // But does accept eval functions
+        for (const definition of evalFunctionsDefinitions) {
+          const {
+            signatures: [firstSignature],
+          } = definition;
+          const fieldMapping = getFieldMapping(firstSignature.params);
+          const printedInvocation = getFunctionSignatures(
+            { ...definition, signatures: [{ ...firstSignature, params: fieldMapping }] },
+            { withTypes: false }
+          )[0].declaration;
+
+          testErrorsAndWarnings(`from a_index | sort ${printedInvocation}`, []);
+        }
+
+        // Expression parts are also validated
+        testErrorsAndWarnings('from a_index | sort sin(stringField)', [
+          'Argument of [sin] must be [number], found value [stringField] type [string]',
+        ]);
+
+        // Expression parts are also validated
+        testErrorsAndWarnings('from a_index | sort numberField + stringField', [
+          'Argument of [+] must be [number], found value [stringField] type [string]',
+        ]);
+      });
     });
 
     describe('enrich', () => {