Those who type as INFJ and INTJ on the Myers and Briggs personality system share a lot of traits and behaviors, which sometimes makes it difficult to tell them apart. This happens because both INFJs and INTJs use Introverted Intuition (Ni) as their dominant function, which means they seek to understand the deeper meaning of life and look for patterns that can help them discover what’s underneath the surface.

No two personality types are the same, however, and INFJ and INTJs will operate differently in many scenarios. Aside from their dominant function, there are important differences in their function stacks to consider. So, even though these types may share similar personality ‘ingredients’, these ingredients combine in different ways to give each type its distinct personality profile.   

INTJ vs. INFJ Differences

If you’re falling into the middle of these types, here are five key differences that may help you to differentiate between the two.

1. INFJs use Fe, INTJs use Te

Though both of these types have Ni as their dominant function, INFJs have Extraverted Feeling (Fe) as their auxiliary function, whereas INTJs operate with Extraverted Thinking (Te). The auxiliary function is like a sidekick to the dominant function, helping the dominant function on its way. 

For INFJs and INTJs, the auxiliary function is an extraverted function, which means it is revealed in how they make decisions in the outer world — it is not just what's happening on the inside. Introverted Feelers, for instance, spend a lot of time reflecting on their own personal values. Extraverted Feelers, on the other hand, are all about supporting, guiding, and nurturing others. The types who have Fe in their function stack value harmony in their relationships and work hard to make sure everyone is on good terms. 

How is this observed? Well, it means the INFJ is that person who, even if deeply introverted, can handle casual chit-chat or difficult conversations when it makes the other person feel at ease. Is it uncomfortable for the INFJ? Possibly, but if the group is happy and in sync, the INFJ is happy too. On the downside, INFJs sometimes take forever to make a decision, because they want to make sure they’re not affecting anyone negatively.

INTJs, on the other hand, are efficiency in a nutshell. Hardworking par excellence, Te-users are the ones you want by your side when a problem comes up, as they’re sure to have a detailed backup plan for every possible scenario. They do all of their Thinking based on facts and logic and are able to set their personal feelings and the feelings of others aside to do the logical thing. 

Fundamentally, INTJs are much more pragmatic than INFJs when it comes to decision-making. You’ll observe an INTJ breaking down a task in small steps, and focusing on the most efficient way to get to their goal. They’re also level-headed in situations where INFJs could easily get overwhelmed. 

Still, this also means that, contrary to their INFJ cousins, INTJs can act a bit emotionally distant, and/or oblivious to other people’s feelings.

 2.  INTJs compete with themselves, INFJs seek self-actualization

As dedicated workers and natural leaders in management positions, INTJs are prone to compete with themselves. These types are often devoted to their professional life or a personal project, sometimes to the point of imbalance. You’ll observe them as being ambitious and eager to produce results, working to perform better today than they did yesterday. Others may describe them as workaholics. 

INFJs, by contrast, are moved by the idea of self-actualization. This means the INFJ seeks to fulfill their personal needs in a holistic, rather than methodical, way. The push is not so much to improve themselves as to be true to themselves, and INFJs will spend a lot of time figuring out who they are and what they stand for; following their own instincts and values in their quest for authenticity. INFJs are very much in-tune with their inner world. Still, this might sometimes lead them to close off from the outside.

3. INFJs feel comfortable talking about their emotions, INTJs not so much

As Fe users, INFJs put great value in expressing their emotions. This doesn’t mean an INFJ will talk about personal matters publicly (they’re Introverts, after all), but they do need an outlet to share their feelings and will usually do so with those who know them well and in whom they trust. In a conflict with a partner, for example, an INFJ will look for a way to express their feelings, so they can move on. Besides talking it out, INFJs can also find writing, painting, and other forms of self-expression useful to work through their feelings.

INTJs, by contrast, have Introverted Feeling (Fi) in their function stack. While they might experience all the feelings on the inside, they don’t naturally feel the urge to express them out loud. In fact, INTJs can feel quite uncomfortable when other people talk about their emotions, or when they’re expected to freely express their own.

4. INTJs are pretty straightforward, INFJs can be more hesitant  

INTJs are usually direct and straightforward in their communication, and generally don’t shy away from asking what they need to do their job well. After all, their main drive is to be efficient, so they’re not that concerned about how people will perceive them, and whether or not they’ll be liked. They just want to get the answer as quickly as possible.  

INFJs have a different approach to communication. First, they often struggle to deliver criticism, as they fear hurting someone’s feelings. Second, they sometimes keep their most precious ideas private until they feel ready to share them with the world. As Fe users, INFJs look for valuable ways to connect with others, so they take their time when making an important decision, pondering how it will affect everyone involved. 

This difference is really obvious in the way these types use language: INTJs speak very precisely and to the point and INFJs speak with more flowery, vague language that will not cause offense. 

5. INTJs love to debate, INFJs avoid heated discussions

As an INFJ who usually gets too emotionally attached in discussions, I admire how eloquently INTJs interact in debate. As Te users, INTJs thrive in conversations that ask for an exchange of ideas and opposite points of view. After all, building coherent arguments is one of the things they’re best at. 

INFJs, on the other hand, don’t have the same ability to keep their cool during a discussion, nor do they handle criticism well. So what do they do? If given the opportunity, they try to escape heated discussions that they know will be emotionally draining for them. 

So if you really can’t tell whether someone is an INTJ or INFJ, strike up a conversation about a really controversial topic that people tend to have strong personal feelings about, like religion or politics. One type will dig in while the other will try to diffuse the tension or remove themselves from the situation entirely. 

INTJ vs. INFJ: The Bottom line

Both INTJs and INFJs share Introverted Intuition in their function stacks, which might sometimes lead to mistyping between the two. But they also exhibit some really obvious differences, whether it’s in the way they communicate, deal with their emotions, or approach conversations. Ultimately, both of these types can learn from each other. After all, your personality type should not be something that limits you, but rather a tool you can use for self-discovery and personal growth.