Not invented here
Not invented here (NIH) is the philosophical principle of not using third party solutions to a problem because of their external origins. It is usually employed in favor of employer's own solution to a given problem, though not necessarily so; NIH's emphasis is on ignoring, boycotting, or otherwise refusing to acknowledge solutions by others.
The reasons for not wanting to use the work of others are varied, but can include fear through lack of understanding of the foreign work, an unwillingness to acknowledge and/or value the work of others (jealousy), or forming part of a wider turf war. As a social phenomenon, this philosophy manifests as an unwillingness to adopt an idea or product because it originates from another culture, a form of tribalism.
The radial tire was patented and innovated by Michelin in France in 1946,  but Americans did not have widespread access to this superior technology until the 1970s. American automobile makers and tire manufacturers called the radial tire "a freak product that isn’t going anywhere." 
In programming, it is also common to refer to the "NIH syndrome" as the tendency towards reinventing the wheel (reimplementing something that is already available) based on the belief that in-house developments are inherently better suited, more secure, more controlled, quicker to develop, and incur lower overall cost (including maintenance cost) than using existing implementations.
Reasoning in favor of the NIH approach includes:
- Third-party components or services mostly do not live up to expectations when high quality is required;
- An entity outside one's own control is a vendor lock-in and a constant threat to business proportional to the repercussions of losing it.
- Closed solutions can be perceived as lacking future unknown flexibility.
These drawbacks are alleviated by:
- Taking an external solution as a base for own development rather than using it as-is;
- Ensuring control of an external entity in case of loss of its supply channel, such as obtaining its source code.
- Appeal to spite
- Association fallacy
- Editor wars
- IKEA effect
- List of cognitive biases
- Wishful thinking
- You aren't gonna need it (YAGNI)
- De facto standard
- "The Innovation Playbook: A Revolution in Business Excellence", Nicholas J. Webb, Chris Thoen, John Wiley and Sons, 2010, ISBN 0-470-63796-X,
- The Cambridge economic history of modern Britain
- HBS.edu P&G's New Innovation Model
- Joel Spolsky (2001-10-14). "In Defense of Not-Invented-Here Syndrome". Joel on Software.
- "Electronic Arts plays hardball". Retrieved 2008-12-29.