diff --git a/packages/mobx/src/api/autorun.ts b/packages/mobx/src/api/autorun.ts
index 4843ad789..e4ba669ad 100644
--- a/packages/mobx/src/api/autorun.ts
+++ b/packages/mobx/src/api/autorun.ts
@@ -171,7 +171,7 @@ export function reaction<T, FireImmediately extends boolean = false>(
             value = nextValue
         })
 
-        // This casting is nesessary as TS cannot infer proper type in current funciton implementation
+        // This casting is nesessary as TS cannot infer proper type in current function implementation
         type OldValue = FireImmediately extends true ? T | undefined : T
         if (firstTime && opts.fireImmediately!) {
             effectAction(value, oldValue as OldValue, r)
diff --git a/packages/mobx/src/types/legacyobservablearray.ts b/packages/mobx/src/types/legacyobservablearray.ts
index 4b1a0ae9a..5ca88d07a 100644
--- a/packages/mobx/src/types/legacyobservablearray.ts
+++ b/packages/mobx/src/types/legacyobservablearray.ts
@@ -71,7 +71,7 @@ export class LegacyObservableArray<T> extends StubArray {
             }
 
             if (safariPrototypeSetterInheritanceBug) {
-                // Seems that Safari won't use numeric prototype setter untill any * numeric property is
+                // Seems that Safari won't use numeric prototype setter until any * numeric property is
                 // defined on the instance. After that it works fine, even if this property is deleted.
                 Object.defineProperty(this, "0", ENTRY_0)
             }
diff --git a/packages/mobx/src/types/observablearray.ts b/packages/mobx/src/types/observablearray.ts
index 3a57b3eab..18f45a1f9 100644
--- a/packages/mobx/src/types/observablearray.ts
+++ b/packages/mobx/src/types/observablearray.ts
@@ -563,7 +563,7 @@ function simpleFunc(funcName) {
     }
 }
 
-// Make sure callbacks recieve correct array arg #2326
+// Make sure callbacks receive correct array arg #2326
 function mapLikeFunc(funcName) {
     return function (callback, thisArg) {
         const adm: ObservableArrayAdministration = this[$mobx]
@@ -575,7 +575,7 @@ function mapLikeFunc(funcName) {
     }
 }
 
-// Make sure callbacks recieve correct array arg #2326
+// Make sure callbacks receive correct array arg #2326
 function reduceLikeFunc(funcName) {
     return function () {
         const adm: ObservableArrayAdministration = this[$mobx]