Vietnamese Days of the Week: Why Monday Is "Second Day" (And How to Actually Learn Them)

Look, you're learning Vietnamese and you need to know how to say the days of the week. Makes sense—you want to make plans, understand when stuff is happening, maybe book that cooking class for Thursday. But when you start looking up Vietnamese days of the week, you hit something weird: Monday translates to "second day." Tuesday is "third day." What the hell happened to day one?

Here's the thing: Vietnamese days of the week are actually pretty logical once you understand the system. But that system has some quirks, and if you're coming from English, it's going to feel backwards at first.

The Basic Vietnamese Week System

Vietnamese uses a number-based system for naming the days of the week. Every weekday (Monday through Saturday) follows the same pattern: thứ + a number.

Here's the full lineup:

The word thứ means "order" or "sequence." It's the same word you use for ordinal numbers in Vietnamese—like saying "2nd" instead of "two." So when Vietnamese speakers say Monday, they're literally saying "the second day."

In spoken Vietnamese, people usually drop the word ngày (day) before each name. So you'll hear "hôm nay thứ hai" (today is Monday) instead of the longer formal version.

Why Monday Is the "Second Day"

This is where it gets interesting. Vietnamese traditionally considers Sunday as the first day of the week. That's why Monday becomes the second day, Tuesday the third, and so on through Saturday as the seventh.

Sunday (Chủ Nhật) breaks the pattern completely. Instead of being "thứ một" (first day), it has its own special name meaning "main day" or "principal day." The word chủ means "master" or "owner," and nhật means "day."

There's actually a historical reason for this. Portuguese Jesuit missionaries introduced this naming system to Vietnam in the early 17th century. They were following the Catholic Church's liturgical calendar, which starts the week with Sunday as the "Lord's Day" and then numbers the remaining weekdays as "second day," "third day," and so on.

If you know Portuguese, you'll recognize the similarity. Portuguese also names weekdays as "segunda-feira" (second day/Monday), "terça-feira" (third day/Tuesday), and so on, with "domingo" (Sunday) as the exception. Vietnamese adopted this Catholic calendar structure but adapted it to fit the Vietnamese language and number system.

Fun fact: Modern Vietnam actually follows the international standard now, starting the calendar week with Monday for business purposes. But the traditional names stuck. So yeah, you're going to be calling Monday "second day" even though everyone treats it like the first day of the work week. Language is weird like that.

Wednesday's Special Case

Quick note on Wednesday (Thứ Tư): Instead of using the regular Vietnamese word bốn for "four," it uses tư, which is the Sino-Vietnamese form borrowed from Chinese. This is just one of those linguistic quirks you'll run into. The Chinese character 四 (meaning "four") gets pronounced as tư in Vietnamese.

Don't overthink it. Just accept that Wednesday breaks the pattern slightly and move on.

Vietnamese Tones Make or Break Your Days

Here's where Vietnamese days of the week get tricky: pronunciation. Vietnamese is a tonal language with six distinct tones, and getting the tone wrong doesn't just sound bad—it changes the meaning entirely.

The word thứ uses a falling-rising tone (the hook mark: ỏ). If you flatten it out or use the wrong tone, you're not saying "ordinal number" anymore—you might be saying something completely different, or just confusing the hell out of whoever you're talking to.

Each day of the week has its own tonal combination:

If you said "Thứ Từ" instead of "Thứ Tư" for Wednesday, you'd be using a falling tone instead of a mid-level tone. That's not just "wrong"—it's a different word. Vietnamese speakers won't know what you're trying to say.

This is why you can't just memorize the romanized spelling and call it done. You need to hear these words spoken by native speakers, repeatedly, until your brain starts recognizing the tonal patterns. We covered this extensively in our Vietnamese tones overview, but the basic point is: tones aren't optional decoration in Vietnamese. They're fundamental to meaning.

Regional accents add another layer. Northern Vietnamese (Hanoi dialect) uses all six tones distinctly. Southern Vietnamese (Ho Chi Minh City dialect) merges some tones together, so they might pronounce certain tones differently than northerners. The words are the same, but the melody changes slightly depending on where you are in Vietnam.

How to Actually Use Vietnamese Days of the Week

Knowing the names is one thing. Using them in sentences is another.

To ask "What day is today?" in Vietnamese, you say: "Hôm nay là ngày thứ mấy?"

Breaking it down:

The answer would be something like: "Hôm nay là thứ hai." (Today is Monday.)

In casual conversation, people drop ngày and just say "Hôm nay thứ mấy?" But stick with the full version until you've got the basics down—shortened forms can come across as too informal with people you don't know well.

Here are some common phrases with days of the week:

The Real Challenge: Learning Days from Textbooks vs. Real Content

Most Vietnamese textbooks and apps will drill you on the days of the week using flashcards or fill-in-the-blank exercises. You'll memorize "thứ hai, thứ ba, thứ tư..." and maybe get tested on them.

Here's the problem: that approach doesn't prepare you for actually using these words in real Vietnamese conversations or content. You need to hear how Vietnamese speakers naturally use days of the week—in context, with proper tones, in sentences that matter.

You're not going to master Vietnamese pronunciation by reading tone marks in a textbook. You need to hear native speakers say these words, over and over, in different contexts. You need to see them used in Vietnamese YouTube videos, Netflix shows, news articles, and social media posts.

That's where immersion learning makes the difference. When you're watching actual Vietnamese content—whether it's a cooking show, a drama series, or a travel vlog—you'll hear days of the week come up naturally. Someone's planning a party for Saturday. A character is explaining why they can't meet on Thursday. A news anchor is discussing events that happened last Monday.

And here's the key: when you hear these words in context, your brain processes them differently than when you're just memorizing a list. You're connecting the word to meaning, to usage, to tone patterns, all at once. That's how you actually learn a language.

Learn Vietnamese Days (and Everything Else) from Real Content

If you want to actually internalize Vietnamese days of the week—with correct tones, natural usage, and the confidence to use them in conversation—you need to learn from real Vietnamese content, not just textbook exercises.

That's what Migaku does. The browser extension lets you watch Vietnamese shows, YouTube videos, or read Vietnamese websites with instant word lookups. You see thứ hai in a sentence, you click it, you get the definition and pronunciation. Then that word goes straight into your spaced repetition deck so you'll review it later when your brain needs the reminder.

You're learning Vietnamese vocabulary and grammar the way native speakers actually use them. Not textbook sentences about hypothetical situations. Real Vietnamese from real content.

The mobile app syncs everything so you can review your flashcards anywhere. And because the cards are based on sentences you actually encountered—sentences that meant something to you because you were interested in the content—they stick way better than generic vocabulary lists.

There's a 10-day free trial if you want to try learning Vietnamese this way. No credit card required, just install the extension and start watching something in Vietnamese.