Stepsibling relationships can be close or virtually nonexistent. Depending on if the stepsiblings live together, their age, and their relationships with their parents, their relationships with one another may flourish or dissolve. The great thing about stepsiblings, however, is they are not forced to be together forever, but instead can choose to have a relationship. This may actually help them build a stronger relationship. Also helpful is that they came from similar situations, and can offer each other advice on how to handle these situations. If you have children, and your children are angry with you, but your stepchildren adore you, your stepchildren may actually help your children see some good in you at times when they are struggling. It is important to nurture and encourage the relationship between stepsiblings, but to avoid forcing them to be friends. Their relationship needs to evolve on its own.

When stepsiblings are fighting, they can be pretty ruthless, as can most siblings. Your biological child may tell your stepchild you will always love her more since you are her real mom. Your stepchild may use the same tactics on your biological child when it comes to your partner. This is normal, but it should be addressed. Discussing with your children and stepchildren that you and your partner love them all no matter who they are biologically related to may help. Also important to address if it comes up is the difference children may feel when some live with you and some live with another biological parent. There may be some competition or concern that you like your stepchildren more since they live with you and your biological children do not. This may happen with your stepchildren and your partner as well. Try and maintain an equal field and their fighting may not be quite as nasty. Fighting will happen, however, and it is a normal occurrence.

To encourage bonding, you could plan your own stepsibling day, and have all of the children suggest activities to take place on that day. Maybe you can have fun with the rivalries and have your children versus your partner's children for some events, girls versus boys for others, and then joint events where you mix the families. Make sure to include at least one event for each child where he or she will excel. For example, potato sack racing may be a strength for your daughter, while name that tune may be a strength for your stepson — include both. Let the children decide what the food will be and if gifts will be exchanged. Be creative and suggest they make gifts for each other. If there are quite a few stepsiblings, suggest they use a grab system. You may want to open the day up to the other biological parents, stepparents, and any stepsiblings who are not related to you or your partner. Make it a day all about them, and there is definitely going to be some bonding!