diff --git a/src/parser/validate.ts b/src/parser/validate.ts
index be3ec157..d9c24215 100644
--- a/src/parser/validate.ts
+++ b/src/parser/validate.ts
@@ -82,7 +82,7 @@ export async function validate(parse: {
 
   function getPresentFlags(flags: Record<string, unknown>): string[] {
     return Object.keys(flags).reduce((acc, key) => {
-      if (flags[key]) acc.push(key)
+      if (flags[key] !== undefined) acc.push(key)
       return acc
     }, [] as string[])
   }
@@ -113,7 +113,7 @@ export async function validate(parse: {
         continue
       if (parse.output.metadata.flags && parse.output.metadata.flags[name]?.setFromDefault)
         continue
-      if (parse.output.flags[flag]) {
+      if (parse.output.flags[flag] !== undefined) {
         return {...base, status: 'failed', reason: `--${flag}=${parse.output.flags[flag]} cannot also be provided when using --${name}`}
       }
     }
@@ -126,7 +126,7 @@ export async function validate(parse: {
     const resolved = await resolveFlags(flags)
     const keys = getPresentFlags(resolved)
     for (const flag of keys) {
-      if (flag !== name && parse.output.flags[flag]) {
+      if (flag !== name && parse.output.flags[flag] !== undefined) {
         return {...base, status: 'failed', reason: `--${flag} cannot also be provided when using --${name}`}
       }
     }
@@ -137,7 +137,7 @@ export async function validate(parse: {
   async function validateDependsOn(name: string, flags: FlagRelationship[]): Promise<Validation> {
     const base = {name, validationFn: 'validateDependsOn'}
     const resolved = await resolveFlags(flags)
-    const foundAll = Object.values(resolved).every(Boolean)
+    const foundAll = Object.values(resolved).every(val => val !== undefined)
     if (!foundAll) {
       const formattedFlags = Object.keys(resolved).map(f => `--${f}`).join(', ')
       return {...base, status: 'failed', reason: `All of the following must be provided when using --${name}: ${formattedFlags}`}
diff --git a/test/parser/validate.test.ts b/test/parser/validate.test.ts
index a64123bc..61183bec 100644
--- a/test/parser/validate.test.ts
+++ b/test/parser/validate.test.ts
@@ -748,6 +748,88 @@ describe('validate', () => {
       })
     })
 
+    it('should pass if the specified flags whose when property resolves to true, flag has a false value', async () => {
+      const input = {
+        argv: [],
+        flags: {
+          cookies: {input: [], name: 'cookies'},
+          sprinkles: {input: [], name: 'sprinkles'},
+          dessert: {
+            input: [],
+            name: 'dessert',
+            relationships: [
+              {
+                type: 'all',
+                flags: [
+                  'sprinkles',
+                  {name: 'cookies', when: async () => Promise.resolve(true)},
+                ],
+              },
+            ],
+          },
+        },
+        args: [],
+        strict: true,
+        context: {},
+        '--': true,
+      }
+
+      const output = {
+        args: {},
+        argv: [],
+        flags: {sprinkles: true, dessert: 'ice-cream', cookies: false},
+        raw: [
+          {type: 'flag', flag: 'sprinkles', input: true},
+          {type: 'flag', flag: 'dessert', input: 'ice-cream'},
+          {type: 'flag', flag: 'cookies', input: false},
+        ],
+        metadata: {},
+      }
+
+      // @ts-expect-error
+      await validate({input, output})
+    })
+
+    it('should fail if the specified flags whose when property resolves to true in exclusive, flag has a false value', async () => {
+      const input = {
+        argv: [],
+        flags: {
+          cookies: {input: [], name: 'cookies'},
+          sprinkles: {input: [], name: 'sprinkles'},
+          dessert: {
+            input: [],
+            name: 'dessert',
+            exclusive: [{name: 'cookies', when: async () => Promise.resolve(true)}],
+          },
+        },
+        args: [],
+        strict: true,
+        context: {},
+        '--': true,
+      }
+
+      const output = {
+        args: {},
+        argv: [],
+        flags: {sprinkles: true, dessert: 'ice-cream', cookies: false},
+        raw: [
+          {type: 'flag', flag: 'sprinkles', input: true},
+          {type: 'flag', flag: 'dessert', input: 'ice-cream'},
+          {type: 'flag', flag: 'cookies', input: false},
+        ],
+        metadata: {},
+      }
+
+      try {
+        // @ts-expect-error
+        await validate({input, output})
+        assert.fail('should have thrown')
+      } catch (error) {
+        const err = error as CLIError
+        expect(err.message).to.include('--cookies=false cannot also be provided when using --dessert')
+      }
+    })
+
     describe('mixed', () => {
       const input = {
         argv: [],