diff --git a/spec/tokenized-buffer-spec.js b/spec/tokenized-buffer-spec.js
index b2324d392..ba43f9ff3 100644
--- a/spec/tokenized-buffer-spec.js
+++ b/spec/tokenized-buffer-spec.js
@@ -807,7 +807,7 @@ describe('TokenizedBuffer', () => {
 
         buffer.setText('  ')
         tokenizedBuffer.toggleLineCommentsForBufferRows(0, 0)
-        expect(buffer.lineForRow(0)).toBe('// ')
+        expect(buffer.lineForRow(0)).toBe('  // ')
 
         buffer.setText('    a\n  \n    b')
         tokenizedBuffer.toggleLineCommentsForBufferRows(0, 2)
diff --git a/src/tokenized-buffer.js b/src/tokenized-buffer.js
index 1d52411ae..4eed4110a 100644
--- a/src/tokenized-buffer.js
+++ b/src/tokenized-buffer.js
@@ -199,17 +199,20 @@ class TokenizedBuffer {
         })
       }
     } else {
-      let allBlank = true
-      let allBlankOrCommented = true
-
+      let hasCommentedLines = false
+      let hasUncommentedLines = false
       for (let row = start; row <= end; row++) {
         const line = this.buffer.lineForRow(row)
-        const blank = line.match(/^\s*$/)
-        if (!blank) allBlank = false
-        if (!blank && !commentStartRegex.testSync(line)) allBlankOrCommented = false
+        if (NON_WHITESPACE_REGEX.test(line)) {
+          if (commentStartRegex.testSync(line)) {
+            hasCommentedLines = true
+          } else {
+            hasUncommentedLines = true
+          }
+        }
       }
 
-      const shouldUncomment = allBlankOrCommented && !allBlank
+      const shouldUncomment = hasCommentedLines && !hasUncommentedLines
 
       if (shouldUncomment) {
         for (let row = start; row <= end; row++) {
@@ -221,15 +224,22 @@ class TokenizedBuffer {
           }
         }
       } else {
-        let minIndentLevel = null
+        let minIndentLevel = Infinity
+        let minBlankIndentLevel = Infinity
         for (let row = start; row <= end; row++) {
           const line = this.buffer.lineForRow(row)
+          const indentLevel = this.indentLevelForLine(line)
           if (NON_WHITESPACE_REGEX.test(line)) {
-            const indentLevel = this.indentLevelForLine(line)
-            if (minIndentLevel == null || indentLevel < minIndentLevel) minIndentLevel = indentLevel
+            if (indentLevel < minIndentLevel) minIndentLevel = indentLevel
+          } else {
+            if (indentLevel < minBlankIndentLevel) minBlankIndentLevel = indentLevel
           }
         }
-        if (minIndentLevel == null) minIndentLevel = 0
+        minIndentLevel = Number.isFinite(minIndentLevel)
+          ? minIndentLevel
+          : Number.isFinite(minBlankIndentLevel)
+              ? minBlankIndentLevel
+              : 0
 
         const tabLength = this.getTabLength()
         const indentString = ' '.repeat(tabLength * minIndentLevel)